TY - JOUR A1 - Lukas, Marcus A1 - Wacker, Alexander T1 - Constraints by oxygen and food quality on carbon pathway regulation: a co-limitation study with an aquatic key herbivore JF - Ecology : a publication of the Ecological Society of America N2 - In food webs, herbivores are often constrained by low food quality in terms of mineral and biochemical limitations, which in aquatic ecosystems can co-occur with limited oxygen conditions. As low food quality implies that carbon (C) is available in excess, and therefore a regulation to get rid of excess C is crucial for the performance of consumers, we examined the C pathways (ingestion, feces release, excretion, and respiration) of a planktonic key herbivore (Daphnia magna). We tested whether consumer C pathways increase due to mineral (phosphorus, P) or biochemical (cholesterol and fatty acid) limitations and how these regulations vary when in addition oxygen is low. Under such conditions, at least the capability of the upregulation of respiration may be restricted. Furthermore, we discussed the potential role of the oxygen-transporting protein hemoglobin (Hb) in the regulation of C budgets. Different food quality constraints led to certain C regulation patterns to increase the removal of excess dietary C: P-limited D. magna increased excretion and respiration, while cholesterol-limited Daphnia in addition upregulated the release of feces. In contrast, the regulative effort was low and only feces release increased when D. magna was limited by a long-chain polyunsaturated fatty acid (eicosapentaenoic acid, EPA). Co-limiting oxygen did not always impact the discharge of excess C. We found the food-quality-induced upregulation of respiration was still present at low oxygen. In contrast, higher excretion of excess C was diminished at low oxygen supply. Besides the effect that the Hb concentration increased under low oxygen, our results indicate a low food-quality-induced increase in the Hb content of the animals. Overall, C budgeting is phenotypically plastic towards different (co-) limiting scenarios. These trigger specific regulation responses that could be the result of evolutionary adaptations. KW - carbon budget KW - carbon stoichiometry KW - cholesterol KW - co-limitation KW - Daphnia KW - EPA KW - hemoglobin KW - oxygen KW - phosphorus KW - polyunsaturated fatty acid KW - zooplankton Y1 - 2014 SN - 0012-9658 SN - 1939-9170 VL - 95 IS - 11 SP - 3068 EP - 3079 PB - Wiley CY - Washington ER - TY - JOUR A1 - Glaeser, Stefanie P. A1 - Berghoff, Bork A. A1 - Stratmann, Verena A1 - Grossart, Hans-Peter A1 - Glaeser, Jens T1 - Contrasting effects of singlet oxygen and hydrogen peroxide on bacterial community composition in a humic lake JF - PLoS one N2 - Light excitation of humic matter generates reactive oxygen species (ROS) in surface waters of aquatic ecosystems. Abundant ROS generated in humic matter rich lakes include singlet oxygen (O-1(2)) and hydrogen peroxide (H2O2). Because these ROS differ in half-life time and toxicity, we compared their effects on microbial activity (C-14-Leucine incorporation) and bacterial community composition (BCC) in surface waters of humic Lake Grosse Fuchskuhle (North-eastern Germany). For this purpose, experiments with water samples collected from the lake were conducted in July 2006, September 2008 and August 2009. Artificially increased O-1(2) and H2O2 concentrations inhibited microbial activity in water samples to a similar extent, but the effect of the respective ROS on BCC varied strongly. BCC analysis by 16S rRNA gene clone libraries and RT-PCR DGGE revealed ROS specific changes in relative abundance and activity of major bacterial groups and composition of dominating phylotypes. These changes were consistent in the three experiments performed in different years. The relative abundance of Polynucleobacter necessarius, Limnohabitans-related phylotypes (Betaproteobacteria), and Novosphingobium acidiphilum (Alphaproteobacteria) increased or was not affected by photo-sensitized O-1(2) exposure, but decreased after H2O2 exposure. The opposite pattern was found for Actinobacteria of the freshwater AcI-B cluster which were highly sensitive to O-1(2) but not to H2O2 exposure. Furthermore, group-specific RT-PCR DGGE analysis revealed that particle-attached P. necessarius and Limnohabitans-related phylotypes exhibit higher resistance to O-1(2) exposure compared to free-living populations. These results imply that O-1(2) acts as a factor in niche separation of closely affiliated Polynucleobacter and Limnohabitans-related phylotypes. Consequently, oxidative stress caused by photochemical ROS generation should be regarded as an environmental variable determining abundance, activity, and phylotype composition of environmentally relevant bacterial groups, in particular in illuminated and humic matter rich waters. Y1 - 2014 U6 - https://doi.org/10.1371/journal.pone.0092518 SN - 1932-6203 VL - 9 IS - 3 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Azuma, Yusuke A1 - Kuekenshoener, Tim A1 - Ma, Guangyong A1 - Yasunaga, Jun-ichiro A1 - Imanishi, Miki A1 - Tanaka, Gen A1 - Nakase, Ikuhiko A1 - Maruno, Takahiro A1 - Kobayashi, Yuji A1 - Arndt, Katja Maren A1 - Matsuoka, Masao A1 - Futaki, Shiroh T1 - Controlling leucine-zipper partner recognition in cells through modification of a-g interactions JF - Chemical communications N2 - By focusing on the a-g interactions, successful design and selection were accomplished to obtain a leucine-zipper segment that discriminates the appropriate partner over another that provides very similar patterns of electrostatic interactions. Y1 - 2014 U6 - https://doi.org/10.1039/c4cc00555d SN - 1359-7345 SN - 1364-548X VL - 50 IS - 48 SP - 6364 EP - 6367 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Gabsi, Faten A1 - Hammers-Wirtz, Monika A1 - Grimm, Volker A1 - Schaeffer, Andreas A1 - Preuss, Thomas G. T1 - Coupling different mechanistic effect models for capturing individual- and population-level effects of chemicals: Lessons from a case where standard risk assessment failed JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog N2 - Current environmental risk assessment (ERA) of chemicals for aquatic invertebrates relies on standardized laboratory tests in which toxicity effects on individual survival, growth and reproduction are measured. Such tests determine the threshold concentration of a chemical below which no population-level effects are expected. How well this procedure captures effects on individuals and populations, however, remains an open question. Here we used mechanistic effect models, combining individual-level reproduction and survival models with an individual-based population model (IBM), to understand the individuals' responses and extrapolate them to the population level. We used a toxicant (Dispersogen A) for which adverse effects on laboratory populations were detected at the determined threshold concentration and thus challenged the conservatism of the current risk assessment method. Multiple toxicity effects on reproduction and survival were reported, in addition to effects on the F1 generation. We extrapolated commonly tested individual toxicity endpoints, reproduction and survival, to the population level using the IBM. Effects on reproduction were described via regression models. To select the most appropriate survival model, the IBM was run assuming either stochastic death (SD) or individual tolerance (IT). Simulations were run for different scenarios regarding the toxicant's effects: survival toxicity, reproductive toxicity, or survival and reproductive toxicity. As population-level endpoints, we used population size and structure and extinction risk. We found that survival represented as SD explained population dynamics better than IT. Integrating toxicity effects on both reproduction and survival yielded more accurate predictions of population effects than considering isolated effects. To fully capture population effects observed at high toxicant concentrations, toxicity effects transmitted to the F1 generation had to be integrated. Predicted extinction risk was highly sensitive to the assumptions about individual-level effects. Our results demonstrate that the endpoints used in current standard tests may not be sufficient for assessing the risk of adverse effects on populations. A combination of laboratory population experiments with mechanistic effect models is a powerful tool to better understand and predict effects on both individuals and populations. Mechanistic effect modelling thus holds great potential to improve the accuracy of ERA of chemicals in the future. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved. KW - Individual-based modelling KW - TK/TD modelling KW - Daphnia magna KW - Risk assessment Y1 - 2014 U6 - https://doi.org/10.1016/j.ecolmodel.2013.06.018 SN - 0304-3800 SN - 1872-7026 VL - 280 SP - 18 EP - 29 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Lukas, Marcus A1 - Wacker, Alexander T1 - Daphnia's dilemma: adjustment of carbon budgets in the face of food and cholesterol limitation JF - The journal of experimental biology N2 - We studied the carbon (C) metabolism in Daphnia when the amount of C (food quantity) and/or the content of biochemical nutrients (food quality) was limiting. Growth performances and C budgets of Daphnia magna (assimilation, faeces egestion, excretion and respiration measured by [C-14]-tracing) were analysed when animals were raised on different food quantities and concentrations of cholesterol, an essential biochemical food compound. Cholesterol is of special interest because it not only acts as limiting nutrient but also contributes to the overall C pool of the animals. As the tissue cholesterol concentration in Daphnia is quite low, we hypothesized the selective exclusion of cholesterol from C budgeting and tested this using radiolabelled cholesterol. Somatic growth rates of D. magna were highest at high quantity and quality and were reduced to a moderate value if either the food quantity or the cholesterol concentration was low. Growth was lowest at low food quantity and quality. The measurements of C budgets revealed high regulative response to low food quality at high food quantity only. Here, low dietary cholesterol caused bulk C assimilation efficiency (AE) to decrease and assimilated (excess) C to be increasingly respired. Additionally, Daphnia enhanced efficient adjustment of C budgets when facing cholesterol limitation by (1) increasing the AE of the cholesterol itself and (2) not changing cholesterol respiration, which was still not detectable. In contrast, at low food quantity, Daphnia is unable to adjust for low food quality, emphasizing that food limitation could overrule food quality effects. KW - Biochemical limitation KW - Carbon budgets KW - Zooplankton KW - Carbon pathway KW - Food quality KW - Food quantity Y1 - 2014 U6 - https://doi.org/10.1242/jeb.094151 SN - 0022-0949 SN - 1477-9145 VL - 217 IS - 7 SP - 1079 EP - 1086 PB - Company of Biologists Limited CY - Cambridge ER - TY - JOUR A1 - Lamanna, Francesco A1 - Kirschbaum, Frank A1 - Tiedemann, Ralph T1 - De novo assembly and characterization of the skeletal muscle and electric organ transcriptomes of the African weakly electric fish Campylomormyrus compressirostris (Mormyridae, Teleostei) JF - Molecular ecology resources N2 - African weakly electric fishes (Mormyridae) underwent an outstanding adaptive radiation (about 200 species), putatively owing to their ability to communicate through species-specific weak electric signals. The electric organ discharge (EOD) is produced by muscle-derived electrocytes organized in piles to form an electric organ. Despite the importance of this trait as a prezygotic isolation mechanism, genomic resources remained limited. We present here a first draft of the skeletal muscle and electric organ transcriptomes from the weakly electric fish species Campylomormyrus compressirostris, obtained using the Illumina HiSeq2000 sequencing technology. Approximately 6.8 Gbp of cDNA sequence data were produced from both tissues, resulting in 57268109 raw reads for the skeletal muscle and 46934923 for the electric organ, and assembled de novo into 46143 and 89270 contigs, respectively. About 50% of both transcriptomes were annotated after protein databases search. The two transcriptomes show similar profiles in terms of Gene Ontology categories composition. We identified several candidate genes which are likely to play a central role in the production and evolution of the electric signal. For most of these genes, and for many other housekeeping genes, we were able to obtain the complete or partial coding DNA sequences (CDS), which can be used for the development of primers to be utilized in qRT-PCR experiments. We present also the complete mitochondrial genome and compare it to those available from other weakly electric fish species. Additionally, we located 1671 SSR-containing regions with their flanking sites and designed the relative primers. This study establishes a first step in the development of genomic tools aimed at understanding the role of electric communication during speciation. KW - cSSR KW - electric fish KW - electric organ KW - skeletal muscle KW - transcriptome Y1 - 2014 U6 - https://doi.org/10.1111/1755-0998.12260 SN - 1755-098X SN - 1755-0998 VL - 14 IS - 6 SP - 1222 EP - 1230 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Feher, Kristen A1 - Lisec, Jan A1 - Roemisch-Margl, Lilla A1 - Selbig, Joachim A1 - Gierl, Alfons A1 - Piepho, Hans-Peter A1 - Nikoloski, Zoran A1 - Willmitzer, Lothar T1 - Deducing hybrid performance from parental metabolic profiles of young primary roots of maize by using a multivariate diallel approach JF - PLoS one Y1 - 2014 U6 - https://doi.org/10.1371/journal.pone.0085435 SN - 1932-6203 VL - 9 IS - 1 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Dey, Pradip A1 - Adamovski, Miriam A1 - Friebe, Simon A1 - Badalyan, Artavazd A1 - Mutihac, Radu-Cristian A1 - Paulus, Florian A1 - Leimkühler, Silke A1 - Wollenberger, Ursula A1 - Haag, Rainer T1 - Dendritic polyglycerol-poly(ethylene glycol)-based polymer networks for biosensing application JF - ACS applied materials & interfaces N2 - This work describes the formation of a new dendritic polyglycerol-poly(ethylene glycol)-based 3D polymer network as a matrix for immobilization of the redox enzyme periplasmatic aldehyde oxidoreductase to create an electrochemical biosensor. The novel network is built directly on the gold surface, where it simultaneously stabilizes the enzyme for up to 4 days. The prepared biosensors can be used for amperometric detection of benzaldehyde in the range of 0.8-400 mu M. KW - biosensors KW - hydrogel KW - amperometry KW - dendritic Y1 - 2014 U6 - https://doi.org/10.1021/am502018x SN - 1944-8244 VL - 6 IS - 12 SP - 8937 EP - 8941 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Mumm, Rebekka A1 - Scheffler, Christiane A1 - Hermanussen, Michael T1 - Developing differential height, weight and body mass index references for girls that reflect the impact of the menarche JF - Acta paediatrica : nurturing the child N2 - Aim Growth is both a matter of amplitude and tempo. We aimed to develop references for body height, body weight and body mass index (BMI) with respect to tempo of maturity. Methods Data obtained from the German KiGGS study (2003-2006) on body height, body weight and presence or absence of the menarche were re-analysed in 3776 girls, aged 10-17years. We developed smoothed centiles for BMI-, body-height- and body-weight-for-age using the LMS method for premenarcheal and postmenarcheal girls. Results Body height, body weight and BMI differed significantly between premenarcheal and postmenarcheal girls. On average, postmenarcheal girls aged 11-17years were 5.3cm taller and 9.7kg heavier, and their BMI was 2.9kg/m2 higher than in premenarcheal girls of the same calendar age. Conclusion Adolescent BMI rises with calendar age and biological age. New reference charts for adolescent girls aged 10-18years were generated to be inserted into the currently used references to avoid misclassifying underweight and overweight pubertal girls. KW - Body mass index KW - Body mass index reference values KW - Menarche KW - Obesity KW - Overweight Y1 - 2014 U6 - https://doi.org/10.1111/apa.12625 SN - 0803-5253 SN - 1651-2227 VL - 103 IS - 7 SP - e312 EP - e316 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Scheiner, Ricarda A1 - Toteva, Anna A1 - Reim, Tina A1 - Sovik, Eirik A1 - Barron, Andrew B. T1 - Differences in the phototaxis of pollen and nectar foraging honey bees are related to their octopamine brain titers JF - Frontiers in physiology N2 - The biogenic amine octopamine is an important neuromodulator, neurohormone and neurotransmitter in insects. We here investigate the role of octopamine signaling in honey bee phototaxis. Our results show that groups of bees differ naturally in their phototaxis. Pollen forgers display a lower light responsiveness than nectar foragers. The lower phototaxis of pollen foragers coincides with higher octopamine titers in the optic lobes but is independent of octopamine receptor gene expression. Increasing octopamine brain titers reduces responsiveness to light, while tyramine application enhances phototaxis. These findings suggest an involvement of octopamine signaling in honey bee phototaxis and possibly division of labor, which is hypothesized to be based on individual differences in sensory responsiveness. KW - biogenic amines KW - tyramine KW - division of labor KW - honey bee KW - light responsiveness KW - insect KW - behavior Y1 - 2014 U6 - https://doi.org/10.3389/fphys.2014.00116 SN - 1664-042X VL - 5 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Mayer, Lena S. A1 - Uciechowski, Peter A1 - Meyer, Sören A1 - Schwerdtle, Tanja A1 - Rink, Lothar A1 - Haase, Hajo T1 - Differential impact of zinc deficiency on phagocytosis, oxidative burst, and production of pro-inflammatory cytokines by human monocytes JF - Metallomics : integrated biometal science Y1 - 2014 U6 - https://doi.org/10.1039/c4mt00051j SN - 1756-5901 SN - 1756-591X VL - 6 IS - 7 SP - 1288 EP - 1295 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Gossner, Martin M. A1 - Pasalic, Esther A1 - Lange, Markus A1 - Lange, Patricia A1 - Boch, Steffen A1 - Hessenmöller, Dominik A1 - Müller, Jörg A1 - Socher, Stephanie A. A1 - Fischer, Markus A1 - Schulze, Ernst-Detlef A1 - Weisser, Wolfgang W. T1 - Differential responses of herbivores and herbivory to management in temperate Eeuropean beech JF - PLoS one N2 - Forest management not only affects biodiversity but also might alter ecosystem processes mediated by the organisms, i.e. herbivory the removal of plant biomass by plant-eating insects and other arthropod groups. Aiming at revealing general relationships between forest management and herbivory we investigated aboveground arthropod herbivory in 105 plots dominated by European beech in three different regions in Germany in the sun-exposed canopy of mature beech trees and on beech saplings in the understorey. We separately assessed damage by different guilds of herbivores, i.e. chewing, sucking and scraping herbivores, gall-forming insects and mites, and leaf-mining insects. We asked whether herbivory differs among different forest management regimes (unmanaged, uneven-aged managed, even-aged managed) and among age-classes within even-aged forests. We further tested for consistency of relationships between regions, strata and herbivore guilds. On average, almost 80% of beech leaves showed herbivory damage, and about 6% of leaf area was consumed. Chewing damage was most common, whereas leaf sucking and scraping damage were very rare. Damage was generally greater in the canopy than in the understorey, in particular for chewing and scraping damage, and the occurrence of mines. There was little difference in herbivory among differently managed forests and the effects of management on damage differed among regions, strata and damage types. Covariates such as wood volume, tree density and plant diversity weakly influenced herbivory, and effects differed between herbivory types. We conclude that despite of the relatively low number of species attacking beech; arthropod herbivory on beech is generally high. We further conclude that responses of herbivory to forest management are multifaceted and environmental factors such as forest structure variables affecting in particular microclimatic conditions are more likely to explain the variability in herbivory among beech forest plots. Y1 - 2014 U6 - https://doi.org/10.1371/journal.pone.0104876 SN - 1932-6203 VL - 9 IS - 8 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Salka, Ivette A1 - Wurzbacher, Christian A1 - Garcia, Sarahi L. A1 - Labrenz, Matthias A1 - Juergens, Klaus A1 - Grossart, Hans-Peter T1 - Distribution of acI-Actinorhodopsin genes in Baltic Sea salinity gradients indicates adaptation of facultative freshwater photoheterotrophs to brackish waters JF - Environmental microbiology Y1 - 2014 SN - 1462-2912 SN - 1462-2920 VL - 16 IS - 2 SP - 586 EP - 597 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Bauer, Barbara A1 - Vos, Matthijs A1 - Klauschies, Toni A1 - Gaedke, Ursula T1 - Diversity, functional similarity, and top-down control drive synchronization and the reliability of ecosystem function JF - The American naturalist : a bi-monthly journal devoted to the advancement and correlation of the biological sciences N2 - The concept that diversity promotes reliability of ecosystem function depends on the pattern that community-level biomass shows lower temporal variability than species-level biomasses. However, this pattern is not universal, as it relies on compensatory or independent species dynamics. When in contrast within--trophic level synchronization occurs, variability of community biomass will approach population-level variability. Current knowledge fails to integrate how species richness, functional distance between species, and the relative importance of predation and competition combine to drive synchronization at different trophic levels. Here we clarify these mechanisms. Intense competition promotes compensatory dynamics in prey, but predators may at the same time increasingly synchronize, under increasing species richness and functional similarity. In contrast, predators and prey both show perfect synchronization under strong top-down control, which is promoted by a combination of low functional distance and high net growth potential of predators. Under such conditions, community-level biomass variability peaks, with major negative consequences for reliability of ecosystem function. KW - biodiversity KW - ecosystem services KW - population dynamics KW - predator-prey system KW - species richness KW - synchrony Y1 - 2014 U6 - https://doi.org/10.1086/674906 SN - 0003-0147 SN - 1537-5323 VL - 183 IS - 3 SP - 394 EP - 409 PB - Univ. of Chicago Press CY - Chicago ER - TY - JOUR A1 - Reim, Tina A1 - Scheiner, Ricarda T1 - Division of labour in honey bees: age- and task-related changes in the expression of octopamine receptor genes JF - Insect molecular biology N2 - The honey bee (Apis melliferaL.) has developed into an important ethological model organism for social behaviour and behavioural plasticity. Bees perform a complex age-dependent division of labour with the most pronounced behavioural differences occurring between in-hive bees and foragers. Whereas nurse bees, for example, stay inside the hive and provide the larvae with food, foragers leave the hive to collect pollen and nectar for the entire colony. The biogenic amine octopamine appears to play a major role in division of labour but the molecular mechanisms involved are unknown. We here investigated the role of two characterized octopamine receptors in honey bee division of labour. AmOctR1 codes for a Ca2+-linked octopamine receptor. AmOctR3/4 codes for a cyclic adenosine monophosphate-coupled octopamine receptor. Messenger RNA expression of AmOctR1 in different brain neuropils correlates with social task, whereas expression of AmOctR3/4 changes with age rather than with social role per se. Our results for the first time link the regulatory role of octopamine in division of labour to specific receptors and brain regions. They are an important step forward in our understanding of complex behavioural organization in social groups. KW - Apis mellifera KW - behavioural plasticity KW - G-protein coupled receptor KW - AmOctR1 KW - AmOctR3 KW - 4 Y1 - 2014 U6 - https://doi.org/10.1111/imb.12130 SN - 0962-1075 SN - 1365-2583 VL - 23 IS - 6 SP - 833 EP - 841 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Thuiller, Wilfried A1 - Muenkemueller, Tamara A1 - Schiffers, Katja H. A1 - Georges, Damien A1 - Dullinger, Stefan A1 - Eckhart, Vincent M. A1 - Edwards, Thomas C. A1 - Gravel, Dominique A1 - Kunstler, Georges A1 - Merow, Cory A1 - Moore, Kara A1 - Piedallu, Christian A1 - Vissault, Steve A1 - Zimmermann, Niklaus E. A1 - Zurell, Damaris A1 - Schurr, Frank Martin T1 - Does probability of occurrence relate to population dynamics? JF - Ecography : pattern and diversity in ecology ; research papers forum N2 - Interestingly, relationships between demographic parameters and occurrence probability did not vary substantially across degrees of shade tolerance and regions. Although they were influenced by the uncertainty in the estimation of the demographic parameters, we found that r was generally negatively correlated with P-occ, while N, and for most regions K, was generally positively correlated with P-occ. Thus, in temperate forest trees the regions of highest occurrence probability are those with high densities but slow intrinsic population growth rates. The uncertain relationships between demography and occurrence probability suggests caution when linking species distribution and demographic models. Y1 - 2014 U6 - https://doi.org/10.1111/ecog.00836 SN - 0906-7590 SN - 1600-0587 VL - 37 IS - 12 SP - 1155 EP - 1166 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Malinova, Irina A1 - Mahlow, Sebastian A1 - Alseekh, Saleh A1 - Orawetz, Tom A1 - Fernie, Alisdair A1 - Baumann, Otto A1 - Steup, Martin A1 - Fettke, Jörg T1 - Double knockout mutants of arabidopsis grown under normal conditions reveal that the plastidial phosphorylase isozyme participates in transitory starch metabolism JF - Plant physiology : an international journal devoted to physiology, biochemistry, cellular and molecular biology, biophysics and environmental biology of plants N2 - In leaves of two starch-related single-knockout lines lacking either the cytosolic transglucosidase (also designated as disproportionating enzyme 2, DPE2) or the maltose transporter (MEX1), the activity of the plastidial phosphorylase isozyme (PHS1) is increased. In both mutants, metabolism of starch-derived maltose is impaired but inhibition is effective at different subcellular sites. Two constitutive double knockout mutants were generated (designated as dpe2-1 x phs1a and mex1 x phs1b) both lacking functional PHS1. They reveal that in normally grown plants, the plastidial phosphorylase isozyme participates in transitory starch degradation and that the central carbon metabolism is closely integrated into the entire cell biology. All plants were grown either under continuous illumination or in a light-dark regime. Both double mutants were compromised in growth and, compared with the single knockout plants, possess less average leaf starch when grown in a light-dark regime. Starch and chlorophyll contents decline with leaf age. As revealed by transmission electron microscopy, mesophyll cells degrade chloroplasts, but degradation is not observed in plants grown under continuous illumination. The two double mutants possess similar but not identical phenotypes. When grown in a light-dark regime, mesophyll chloroplasts of dpe2-1 x phs1a contain a single starch granule but under continuous illumination more granules per chloroplast are formed. The other double mutant synthesizes more granules under either growth condition. In continuous light, growth of both double mutants is similar to that of the parental single knockout lines. Metabolite profiles and oligoglucan patterns differ largely in the two double mutants. Y1 - 2014 U6 - https://doi.org/10.1104/pp.113.227843 SN - 0032-0889 SN - 1532-2548 VL - 164 IS - 2 SP - 907 EP - 921 PB - American Society of Plant Physiologists CY - Rockville ER - TY - JOUR A1 - Pajoro, Alice A1 - Madrigal, Pedro A1 - Muino, Jose M. A1 - Tomas Matus, Jose A1 - Jin, Jian A1 - Mecchia, Martin A. A1 - Debernardi, Juan M. A1 - Palatnik, Javier F. A1 - Balazadeh, Salma A1 - Arif, Muhammad A1 - Wellmer, Frank A1 - Krajewski, Pawel A1 - Riechmann, Jose-Luis A1 - Angenent, Gerco C. A1 - Kaufmann, Kerstin T1 - Dynamics of chromatin accessibility and gene regulation by MADS-domain transcription factors in flower development JF - Genome biology : biology for the post-genomic era N2 - Background: Development of eukaryotic organisms is controlled by transcription factors that trigger specific and global changes in gene expression programs. In plants, MADS-domain transcription factors act as master regulators of developmental switches and organ specification. However, the mechanisms by which these factors dynamically regulate the expression of their target genes at different developmental stages are still poorly understood. Results: We characterized the relationship of chromatin accessibility, gene expression, and DNA binding of two MADS-domain proteins at different stages of Arabidopsis flower development. Dynamic changes in APETALA1 and SEPALLATA3 DNA binding correlated with changes in gene expression, and many of the target genes could be associated with the developmental stage in which they are transcriptionally controlled. We also observe dynamic changes in chromatin accessibility during flower development. Remarkably, DNA binding of APETALA1 and SEPALLATA3 is largely independent of the accessibility status of their binding regions and it can precede increases in DNA accessibility. These results suggest that APETALA1 and SEPALLATA3 may modulate chromatin accessibility, thereby facilitating access of other transcriptional regulators to their target genes. Conclusions: Our findings indicate that different homeotic factors regulate partly overlapping, yet also distinctive sets of target genes in a partly stage-specific fashion. By combining the information from DNA-binding and gene expression data, we are able to propose models of stage-specific regulatory interactions, thereby addressing dynamics of regulatory networks throughout flower development. Furthermore, MADS-domain TFs may regulate gene expression by alternative strategies, one of which is modulation of chromatin accessibility. KW - Flower Development KW - Floral Organ KW - Floral Meristem KW - Chromatin Accessibility KW - Growth Regulate Factor Y1 - 2014 U6 - https://doi.org/10.1186/gb-2014-15-3-r41 SN - 1465-6906 SN - 1474-760X VL - 15 PB - BioMed Central CY - London ER - TY - JOUR A1 - Xiang, Hai A1 - Gao, Jianqiang A1 - Yu, Baoquan A1 - Zhou, Hui A1 - Cai, Dawei A1 - Zhang, Youwen A1 - Chen, Xiaoyong A1 - Wang, Xi A1 - Hofreiter, Michael A1 - Zhao, Xingbo T1 - Early Holocene chicken domestication in northern China JF - Proceedings of the National Academy of Sciences of the United States of America N2 - Chickens represent by far the most important poultry species, yet the number, locations, and timings of their domestication have remained controversial for more than a century. Here we report ancient mitochondrial DNA sequences from the earliest archaeological chicken bones from China, dating back to similar to 10,000 B.P. The results clearly show that all investigated bones, including the oldest from the Nanzhuangtou site, are derived from the genus Gallus, rather than any other related genus, such as Phasianus. Our analyses also suggest that northern China represents one region of the earliest chicken domestication, possibly dating as early as 10,000 y B.P. Similar to the evidence from pig domestication, our results suggest that these early domesticated chickens contributed to the gene pool of modern chicken populations. Moreover, our results support the idea that multiple members of the genus Gallus, specifically Gallus gallus and Gallus sonneratii contributed to the gene pool of the modern domestic chicken. Our results provide further support for the growing evidence of an early mixed agricultural complex in northern China. KW - ancient DNA KW - chicken KW - domestication KW - species origin Y1 - 2014 U6 - https://doi.org/10.1073/pnas.1411882111 SN - 0027-8424 VL - 111 IS - 49 SP - 17564 EP - 17569 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Lange, Markus A1 - Türke, Manfred A1 - Pasalic, Esther A1 - Boch, Steffen A1 - Hessenmöller, Dominik A1 - Müller, Jörg A1 - Prati, Daniel A1 - Socher, Stephanie A. A1 - Fischer, Markus A1 - Weisser, Wolfgang W. A1 - Gossner, Martin M. T1 - Effects of forest management on ground-dwelling beetles (Coleoptera; Carabidae, Staphylinidae) in Central Europe are mainly mediated by changes in forest structure JF - Forest ecology and management N2 - Forest management is known to influence species diversity of various taxa but inconsistent or even contrasting effects are reported for arthropods. Regional differences in management as well as differences in regional species pools might be responsible for these inconsistencies, but, inter-regional replicated studies that account for regional variability are rare. We investigated the effect of forest type on the abundance, diversity, community structure and composition of two important ground-dwelling beetle families, Carabidae and Staphylinidae, in 149 forest stands distributed over three regions in Germany. In particular we focused on recent forestry history, stand age and dominant tree species, in addition to a number of environmental descriptors. Overall management effects on beetle communities were small and mainly mediated by structural habitat parameters such as the cover of forest canopy or the plant diversity on forest stands. The general response of both beetle taxa to forest management was similar in all regions: abundance and species richness of beetles was higher in older than in younger stands and species richness was lower in unmanaged than in managed stands. The abundance ratio of forest species-to-open habitat species differed between regions, but generally increased from young to old stands, from coniferous to deciduous stands and from managed to unmanaged stands. The response of both beetle families to dominant tree species was variable among regions and staphylinid richness varied in the response to recent forestry history. Our results suggest that current forest management practices change the composition of ground-dwelling beetle communities mainly by favoring generalists and open habitat species. To protect important forest beetle communities and thus the ecosystem functions and services provided by them, we suggest to shelter remaining ancient forests and to develop near-to-nature management strategies by prolonging rotation periods and increasing structural diversity of managed forests. Possible geographic variations in the response of beetle communities need to be considered in conservation-orientated forest management strategies. (C) 2014 Elsevier B.V. All rights reserved. KW - Beech forest KW - Biodiversity Exploratories KW - Conifer plantations KW - Habitat preferences KW - Insects KW - Land use Y1 - 2014 U6 - https://doi.org/10.1016/j.foreco.2014.06.012 SN - 0378-1127 SN - 1872-7042 VL - 329 SP - 166 EP - 176 PB - Elsevier CY - Amsterdam ER -