TY - JOUR A1 - Dennis, Alice B. A1 - Patel, Vilas A1 - Oliver, Kerry M. A1 - Vorburger, Christoph T1 - Parasitoid gene expression changes after adaptation to symbiont-protected hosts JF - Evolution N2 - Reciprocal selection between aphids, their protective endosymbionts, and the parasitoid wasps that prey upon them offers an opportunity to study the basis of their coevolution. We investigated adaptation to symbiont‐conferred defense by rearing the parasitoid wasp Lysiphlebus fabarum on aphids (Aphis fabae) possessing different defensive symbiont strains (Hamiltonella defensa). After ten generations of experimental evolution, wasps showed increased abilities to parasitize aphids possessing the H. defensa strain they evolved with, but not aphids possessing the other strain. We show that the two symbiont strains encode different toxins, potentially creating different targets for counter‐adaptation. Phenotypic and behavioral comparisons suggest that neither life‐history traits nor oviposition behavior differed among evolved parasitoid lineages. In contrast, comparative transcriptomics of adult female wasps identified a suite of differentially expressed genes among lineages, even when reared in a common, symbiont‐free, aphid host. In concurrence with the specificity of each parasitoid lineages’ infectivity, most differentially expressed parasitoid transcripts were also lineage‐specific. These transcripts are enriched with putative venom toxins and contain highly expressed, potentially defensive viral particles. Together, these results suggest that wild populations of L. fabarum employ a complicated offensive arsenal with sufficient genetic variation for wasps to adapt rapidly and specifically to their hosts’ microbial defenses. KW - Adaptation KW - experimental evolution KW - gene expression KW - Lysiphlebus fabarum KW - parasitoid KW - venom Y1 - 2017 U6 - https://doi.org/10.1111/evo.13333 SN - 0014-3820 SN - 1558-5646 VL - 71 SP - 2599 EP - 2617 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Witt, Barbara A1 - Ebert, Franziska A1 - Meyer, Sören A1 - Francesconi, Kevin A. A1 - Schwerdtle, Tanja T1 - Assessing neurodevelopmental effects of arsenolipids in pre-differentiated human neurons JF - Molecular nutrition & food research : bioactivity, chemistry, immunology, microbiology, safety, technology N2 - Scope: In the general population exposure to arsenic occurs mainly via diet. Highest arsenic concentrations are found in seafood, where arsenic is present predominantly in its organic forms including arsenolipids. Since recent studies have provided evidence that arsenolipids could reach the brain of an organism and exert toxicity in fully differentiated human neurons, this work aims to assess the neurodevelopmental toxicity of arsenolipids. Methods and results: Neurodevelopmental effects of three arsenic-containing hydrocarbons (AsHC), two arsenic-containing fatty acids (AsFA), arsenite and dimethylarsinic acid (DMA(V)) were characterized in pre-differentiated human neurons. AsHCs and arsenite caused substantial cytotoxicity in a similar, low concentration range, whereas AsFAs and DMA(V) were less toxic. AsHCs were highly accessible for cells and exerted pronounced neurodevelopmental effects, with neurite outgrowth and the mitochondrial membrane potential being sensitive endpoints; arsenite did not substantially decrease those two endpoints. In fully differentiated neurons, arsenite and AsHCs caused neurite toxicity. Conclusion: These results indicate for a neurodevelopmental potential of AsHCs. Taken into account the possibility that AsHCs might easily reach the developing brain when exposed during early life, neurotoxicity and neurodevelopmental toxicity cannot be excluded. Further studies are needed in order to progress the urgently needed risk assessment. KW - Arsenic-containing fatty acids KW - Arsenic-containing hydrocarbons KW - Arsenite KW - Arsenolipids KW - Neurodevelopmental toxicity Y1 - 2017 U6 - https://doi.org/10.1002/mnfr.201700199 SN - 1613-4125 SN - 1613-4133 VL - 61 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Mao, Hailiang A1 - Aryal, Bibek A1 - Langenecker, Tobias A1 - Hagmann, Jorg A1 - Geisler, Markus A1 - Grebe, Markus T1 - Arabidopsis BTB/POZ protein-dependent PENETRATION3 trafficking and disease susceptibility JF - Nature plants N2 - The outermost cell layer of plant roots (epidermis) constantly encounters environmental challenges. The epidermal outer plasma membrane domain harbours the PENETRATION3 (PEN3)/ABCG36/PDR8 ATP-binding cassette transporter that confers non-host resistance to several pathogens. Here, we show that the Arabidopsis ENDOPLASMIC RETICULUM-ARRESTED PEN3 (EAP3) BTB/POZ-domain protein specifically mediates PEN3 exit from the endoplasmic reticulum and confers resistance to a root-penetrating fungus, providing prime evidence for BTB/POZ-domain protein-dependent membrane trafficking underlying disease resistance. Y1 - 2017 U6 - https://doi.org/10.1038/s41477-017-0039-z SN - 2055-026X SN - 2055-0278 VL - 3 SP - 854 EP - 858 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Aichner, Bernhard A1 - Hilt, Sabine A1 - Perillon, Cecile A1 - Gillefalk, Mikael A1 - Sachse, Dirk T1 - Biosynthetic hydrogen isotopic fractionation factors during lipid synthesis in submerged aquatic macrophytes: Effect of groundwater discharge and salinity JF - Organic geochemistry : the international journal for rapid publication of current research in organic geochemistry and biochemistry N2 - Sedimentary lipid biomarkers have become widely used tools for reconstructing past climatic and ecological changes due to their ubiquitous occurrence in lake sediments. In particular, the hydrogen isotopic composition (expressed as delta D values) of leaf wax lipids derived from terrestrial plants has been a focus of research during the last two decades and the understanding of competing environmental and plant physiological factors influencing the delta D values has greatly improved. Comparatively less attention has been paid to lipid biomarkers derived from aquatic plants, although these compounds are abundant in many lacustrine sediments. We therefore conducted a field and laboratory experiment to study the effect of salinity and groundwater discharge on the isotopic composition of aquatic plant biomarkers. We analyzed samples of the common submerged plant species, Potamogeton pectinatus (sago pondweed), which has a wide geographic distribution and can tolerate high salinity. We tested the effect of groundwater discharge (characterized by more negative delta D values relative to lake water) and salinity on the delta D values of n-alkanes from P. pectinatus by comparing plants (i) collected from the oligotrophic freshwater Lake Stechlin (Germany) at shallow littoral depth from locations with and without groundwater discharge, and (ii) plants grown from tubers collected from the eutrophic Lake Muggelsee in nutrient solution at four salinity levels. Isotopically depleted groundwater did not have a significant influence on the delta D values of n-alkanes in Lake Stechlin P. pectinatus and calculated isotopic fractionation factors epsilon(l/w) between lake water and n-alkanes averaged -137 +/- 9%(n-C-23), -136 +/- 7%(n-C-25) and -131 +/- 6%(n-C-27), respectively. Similar epsilon values were calculated for plants from Lake Muggelsee grown in freshwater nutrient solution (-134 +/- 11% for n-C-23), while greater fractionation was observed at increased salinity values of 10 (163 +/- 12%) and 15(-172 +/- 15%). We therefore suggest an average e value of -136 +/- 9% between source water and the major n-alkanes in P. pectinatus grown under freshwater conditions. Our results demonstrate that isotopic fractionation can increase by 30-40% at salinity values 10 and 15. These results could be explained either by inhibited plant growth at higher salinity, or by metabolic adaptation to salt stress that remain to be elucidated. A potential salinity effect on dD values of aquatic lipids requires further examination, since this would impact on the interpretation of downcore isotopic data in paleohydrologic studies. (C) 2017 Elsevier Ltd. All rights reserved. Y1 - 2017 U6 - https://doi.org/10.1016/j.orggeochem.2017.07.021 SN - 0146-6380 VL - 113 SP - 10 EP - 16 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Romero-Diaz, Cristina A1 - Breedveld, Merel Cathelijne A1 - Fitze, Patrick S. T1 - Climate Effects on Growth, Body Condition, and Survival Depend on the Genetic Characteristics of the Population JF - The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences N2 - Climatic change is expected to affect individual life histories and population dynamics, potentially increasing vulnerability to extinction. The importance of genetic diversity has been highlighted for adaptation and population persistence. However, whether responses of life-history traits to a given environmental condition depend on the genetic characteristics of a population remains elusive. Here we tested this hypothesis in the lizard Zootoca vivipara by simultaneously manipulating habitat humidity, a major climatic predictor of Zootoca’s distribution, and adult male color morph frequency, a trait with genome-wide linkage. Interactive effects of humidity and morph frequency had immediate effects on growth and body condition of juveniles and yearlings, as well as on adult survival, and delayed effects on offspring size. In yearlings, higher humidity led to larger female body size and lower humidity led to higher male compared to female survival. In juveniles and yearlings, some treatment effects were compensated over time. The results show that individual responses to environmental conditions depend on the population’s color morph frequency, age class, and sex and that these affect intra– and inter–age class competition. Moreover, humidity affected the competitive environment rather than imposing trait-based selection on specific color morphs. This indicates that species’ responses to changing environments (e.g., to climate change) are highly complex and difficult to accurately reconstruct and predict without information on the genetic characteristics and demographic structure of populations. KW - age-structured populations KW - age class effects KW - life-history traits KW - Zootoca vivipara KW - humidity KW - color morph frequency Y1 - 2017 U6 - https://doi.org/10.1086/693780 SN - 0003-0147 SN - 1537-5323 VL - 190 SP - 649 EP - 662 PB - Univ. of Chicago Press CY - Chicago ER - TY - JOUR A1 - Javanainen, Matti A1 - Martinez-Seara, Hector A1 - Metzler, Ralf A1 - Vattulainen, Ilpo T1 - Diffusion of Integral Membrane Proteins in Protein-Rich Membranes JF - The journal of physical chemistry letters N2 - The lateral diffusion of embedded proteins along lipid membranes in protein-poor conditions has been successfully described in terms of the Saffman-Delbruck (SD) model, which predicts that the protein diffusion coefficient D is weakly dependent on its radius R as D proportional to ln(1/R). However, instead of being protein-poor, native cell membranes are extremely crowded with proteins. On the basis of extensive molecular simulations, we here demonstrate that protein crowding of the membrane at physiological levels leads to deviations from the SD relation and to the emergence of a stronger Stokes-like dependence D proportional to 1/R. We propose that this 1/R law mainly arises due to geometrical factors: smaller proteins are able to avoid confinement effects much better than their larger counterparts. The results highlight that the lateral dynamics in the crowded setting found in native membranes is radically different from protein-poor conditions and plays a significant role in formation of functional multiprotein complexes. Y1 - 2017 U6 - https://doi.org/10.1021/acs.jpclett.7b01758 SN - 1948-7185 VL - 8 SP - 4308 EP - 4313 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Steinhöfel, Grit A1 - Breuer, Jörn A1 - von Blanckenburg, Friedhelm A1 - Horn, Ingo A1 - Sommer, Michael T1 - The dynamics of Si cycling during weathering in two small catchments in the Black Forest (Germany) traced by Si isotopes JF - Chemical geology : official journal of the European Association for Geochemistry N2 - Silicon stable isotopes have emerged as a powerful proxy to investigate weathering because Si uptake from solution by secondary minerals or by the vegetation causes significant shifts in the isotope composition. In this study, we determined the Si isotope compositions of the principle Si pools within two small catchments located on sandstone and paragneiss, respectively, in the temperate Black Forest (Germany). At both settings, clay formation is dominated by mineral transformation preserving largely the signature of parental minerals with delta Si-30 values of around -0.7%. Bulk soils rich in primary minerals are similar to bulk parental material with delta Si-30 values close to -0.4%. Topsoils are partly different because organic matter degradation has promoted intense weathering leading to delta Si-30 values as low as -1.0%. Water samples expose highly dynamic weathering processes in the soil zone: 1) after spring snowmelt, increased release of DOC and high water fluxes trigger clay mineral dissolution which leads to delta Si-30 values down to -0.7% and 2) in course of the summer, Si uptake by the vegetation and secondary mineral formation drives dissolved Si to typical positive delta Si-30 values up to 1.1%. Groundwater with delta Si-30 values of around 0.4% records steady processes in bedrock reflecting plagioclase weathering together with kaolinite precipitation. An isotope mass balance approach reveals incongruent weathering conditions where denudation of Si is largely driven by physical erosion. Erosion of phytoliths contributes 3 to 21% to the total Si export flux, which is in the same order as the dissolved Si flux. These results elucidate the Si dynamics during weathering on catchments underlain of sedimentary origin, prevailing on the Earth surface and provide therefore valuable information to interpret the isotope signature of large river systems. KW - Weathering KW - Sedimentary rocks KW - Biogeochemical Si cycle KW - Silicon isotopes KW - UV femtosecond laser ablation Y1 - 2017 U6 - https://doi.org/10.1016/j.chemgeo.2017.06.026 SN - 0009-2541 SN - 1878-5999 VL - 466 SP - 389 EP - 402 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Chladkova, Katerina A1 - Hamann, Silke A1 - Williams, Daniel A1 - Hellmuth, Sam T1 - F2 slope as a Perceptual Cue for the Front-Back Contrast in Standard Southern British English JF - Language and speech N2 - Acoustic studies of several languages indicate that second-formant (F2) slopes in high vowels have opposing directions (independent of consonantal context): front [i.]-like vowels are produced with a rising F2 slope, whereas back [u.]-like vowels are produced with a falling F2 slope. The present study first reports acoustic measurements that confirm this pattern for the English variety of Standard Southern British English (SSBE), where /u./ has shifted from the back to the front area of the vowel space and is now realized with higher midpoint F2 values than several decades ago. Subsequently, we test whether the direction of F2 slope also serves as a reliable cue to the /i.// u./ contrast in perception. The findings show that F2 slope direction is used as a cue (additional to midpoint formant values) to distinguish /i./ from /u./by both young and older Standard Southern British English listeners: an otherwise ambiguous token is identified as /i./if it has a rising F2 slope and as /u./if it has a falling F2 slope. Furthermore, our results indicate that listeners generalize their reliance on F2 slope to other contrasts, namely /epsilon/-/./and /ae/-/./, even though F2 slope is not employed to differentiate these vowels in production. This suggests that in Standard Southern British English, a rising F2 seems to be perceptually associated with an abstract feature such as [+ front], whereas a falling F2 with an abstract feature such as [-front]. KW - perceptual cues KW - front-back contrast KW - /u./-fronting KW - Standard Southern British English KW - vowel perception KW - phonological feature Y1 - 2017 U6 - https://doi.org/10.1177/0023830916650991 SN - 0023-8309 SN - 1756-6053 VL - 60 SP - 377 EP - 398 PB - Sage Publ. CY - London ER - TY - JOUR A1 - Brune, Sascha A1 - Corti, Giacomo A1 - Ranalli, Giorgio T1 - Controls of inherited lithospheric heterogeneity on rift linkage: Numerical and analog models of interaction between the Kenyan and Ethiopian rifts across the Turkana depression JF - Tectonics N2 - Inherited rheological structures in the lithosphere are expected to have large impact on the architecture of continental rifts. The Turkana depression in the East African Rift connects the Main Ethiopian Rift to the north with the Kenya rift in the south. This region is characterized by a NW-SE trending band of thinned crust inherited from a Mesozoic rifting event, which is cutting the present-day N-S rift trend at high angle. In striking contrast to the narrow rifts in Ethiopia and Kenya, extension in the Turkana region is accommodated in subparallel deformation domains that are laterally distributed over several hundred kilometers. We present both analog experiments and numerical models that reproduce the along-axis transition from narrow rifting in Ethiopia and Kenya to a distributed deformation within the Turkana depression. Similarly to natural observations, our models show that the Ethiopian and Kenyan rifts bend away from each other within the Turkana region, thus forming a right-lateral step over and avoiding a direct link to form a continuous N-S depression. The models reveal five potential types of rift linkage across the preexisting basin: three types where rifts bend away from the inherited structure connecting via a (1) wide or (2) narrow rift or by (3) forming a rotating microplate, (4) a type where rifts bend towards it, and (5) straight rift linkage. The fact that linkage type 1 is realized in the Turkana region provides new insights on the rheological configuration of the Mesozoic rift system at the onset of the recent rift episode. Plain Language Summary The Turkana depression in the Kenya/Ethiopia borderland is most famous for its several million years old human fossils, but it also holds a rich geological history of continental separation. The Turkana region is a lowland located between the East African and Ethiopian domes because its crust and mantle have been stretched in a continent-wide rift event during Cretaceous times about 140-120 Ma ago. This thin lithosphere exerted paramount control on the dynamics of East African rifting in this area, which commenced around 15 Ma ago and persists until today. Combining analog "sandbox" experiments with numerical geodynamic modeling, we find that inherited rift structures explain the dramatic change in rift style from deep, narrow rift basins north and south of the Turkana area to wide, distributed deformation within the Turkana depression. The failed Cretaceous rift is also responsible for the eastward bend of the Ethiopian rift and the westward bend of the Kenyan rift when entering the Turkana depression, which generated the characteristic hook-shaped form of present-day Lake Turkana. Combing two independent modeling techniques-analog and numerical experiments-is a very promising approach allowing to draw robust conclusions about the processes that shape the surface of our planet. KW - continental rifting KW - east African rift KW - numerical modeling KW - analog modeling KW - tectonic inheritance KW - Turkana depression Y1 - 2017 U6 - https://doi.org/10.1002/2017TC004739 SN - 0278-7407 SN - 1944-9194 VL - 36 SP - 1767 EP - 1786 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Jap, Bernard A. J. A1 - Borleffs, Elisabeth A1 - Maassen, Ben A. M. T1 - Towards identifying dyslexia in Standard Indonesian: the development of a reading assessment battery JF - Reading and writing : an interdisciplinary journal KW - Standard Indonesian KW - Dyslexia KW - Transparent orthography KW - Dyslexia assessment Y1 - 2017 U6 - https://doi.org/10.1007/s11145-017-9748-y SN - 0922-4777 SN - 1573-0905 VL - 30 SP - 1729 EP - 1751 PB - Springer CY - Dordrecht ER -