Ocean Acidification Accelerates Reef Bioerosion

In the recent discussion how biotic systems may react to ocean acidification caused by the rapid rise in carbon dioxide partial pressure (pCO₂) in the marine realm, substantial research is devoted to calcifiers such as stony corals. The antagonistic process – biologically induced carbonate dissolution via bioerosion – has largely been neglected. Unlike skeletal growth, we expect bioerosion by chemical means to be facilitated in a high-CO₂ world. This study focuses on one of the most detrimental bioeroders, the sponge Cliona orientalis, which attacks and kills live corals on Australia’s Great Barrier Reef. Experimental exposure to lowered and elevated levels of pCO₂ confirms a significant enforcement of the sponges’ bioerosion capacity with increasing pCO₂ under more acidic conditions. Considering the substantial contribution of sponges to carbonate bioerosion, this finding implies that tropical reef ecosystems are facing the combined effects of weakened coral calcification and accelerated bioerosion, resulting in critical pressure on the dynamic balance between biogenic carbonate build-up and degradation.     

Universal Internucleotide Statistics in Full Genomes: A Footprint of the DNA Structure and Packaging?

Uncovering the fundamental laws that govern the complex DNA structural organization remains challenging and is largely based upon reconstructions from the primary nucleotide sequences. Here we investigate the distributions of the internucleotide intervals and their persistence properties in complete genomes of various organisms from Archaea and Bacteria to H. Sapiens aiming to reveal the manifestation of the universal DNA architecture. We find that in all considered organisms the internucleotide interval distributions exhibit the same -exponential form. While in prokaryotes a single -exponential function makes the best fit, in eukaryotes the PDF contains additionally a second -exponential, which in the human genome makes a perfect approximation over nearly 10 decades. We suggest that this functional form is a footprint of the heterogeneous DNA structure, where the first -exponential reflects the universal helical pitch that appears both in pro- and eukaryotic DNA, while the second -exponential is a specific marker of the large-scale eukaryotic DNA organization.     

Habitatpr?ferenzen, Dynamik der Raumnutzung und Bestandsstruktur bei Dorfamseln (Turdus merula)

Zusammenfassung In fünf Montandörfern bei Innsbruck/Tirol und zwei Probeflächen der Stadt wurde der Bestand der Amsel in 2 Winterhalbjahren und 2 bis 6 Brutperioden 1982–1987 untersucht. Die Siedlungsdichte nahm von bäuerlichen Dörfern höherer Montanlagen bis in Stadtbereiche Innsbrucks stark zu und zeigte deutliche Beziehungen zur Länge der Strauchschichtgrenzlinie in den einzelnen Probeflächen. Die Reviere waren sowohl in den städtischen als auch dörflichen Untersuchungsarealen sehr inhomogen verteilt. In den Dörfern wurden ältere Gartensiedlungen deutlich präferiert; zentrale Bauerndorfkerne waren am dünnsten besiedelt. Die Brutbestandsfluktuationen waren in zwei über 6 Jahre kontrollierten Dörfern insgesamt gering (9–15% Variationskoeffizient). Hingegen verdreifachte sich die Zahl der Amselreviere im Teilbereich eines Dorfes im Zuge zunehmender Durchgrünung von 1982 bis 1987. In der Nachbrutzeit gab es grundsätzliche Unterschiede in der Dynamik dörflicher und städtischer Amselpopulationen. Mit zunehmend urbanem Siedlungscharakter nahm offensichtlich nicht nur die Amplitude der saisonalen Bestandsoszillationen ab, sondern auch der Anteil von Standvögeln und insbesondere überwinternder Weibchen zu. Innerhalb der Dorflandschaften wechselte die Nutzungsintensität nahe benachbarter Teilareale kurzfristig und kleinräumig. Vor allem vom Herbst zum Winter waren Präferenzwechsel zwischen randlichen Gartensiedlungen und Obstanlagen und zentraleren, bäuerlichen Dorfbereichen auffällig.

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Habitat preferences and seasonal dynamics of space atilization in Blackbirds (Turdus merula) living in villages

Summary Between 1982 and 1987, habitat selection, seasonal changes in population densities and microspace use as well as fluctuations of breeding populations of the Blackbird were investigated in five mountain villages near Innsbruck, Tyrol. Results are compared with data from two city plots. The breeding density of Blackbirds increased dramatically (tenfold) from farmhouse dominated villages to suburbanlike village plots and to urban areas in the city of Innsbruck. There was a distinct relationship between the number of territories and the length of shrub layer boundaries. Remarkable differences in density existed between structurally different parts of the sample plots. These differences also correlated with the amount of vegetation cover available but were also related to other features of village subareas (e.g. density and character of buildings). The fluctuations of population levels within six years were surprisingly low in two villages (coefficients of variation 9 to 15%). In parts of one village, however, the number of blackbird territories tripled with an increase of the vegetation cover at the same time. In postbreeding season fundamental differences in the dynamics of village and suburban to urban populations were noticed. This is true for the amount of the population oszillations (lower with increasing urbanization) as well as for sex ratio in wintering populations (higher proportions of femals in suburban and city plots). Short-term shifts in habitat preferences were obvious within the village plots in the course of the year. Whereas orchards and older residential areas with rich shrub and tree layers at the village edges were heavily utilized by Blackbirds in autumn, the village centres were preferred in winter.

     

Neuropeptides Control the Dynamic Behavior of Airway Mucosal Dendritic Cells

The airway mucosal epithelium is permanently exposed to airborne particles. A network of immune cells patrols at this interface to the environment. The interplay of immune cells is orchestrated by different mediators. In the current study we investigated the impact of neuronal signals on key functions of dendritic cells (DC). Using two-photon microscopic time-lapse analysis of living lung sections from CD11c-EYFP transgenic mice we studied the influence of neuropeptides on airway DC motility. Additionally, using a confocal microscopic approach, the phagocytotic capacity of CD11c⁺ cells after neuropeptide stimulation was determined. Electrical field stimulation (EFS) leads to an unspecific release of neuropeptides from nerves. After EFS and treatment with the neuropeptides vasoactive intestinal peptide (VIP) or calcitonin gene-related peptide (CGRP), airway DC in living lung slices showed an altered motility. Furthermore, the EFS-mediated effect could partially be blocked by pre-treatment with the receptor antagonist CGRP_8–37. Additionally, the phagocytotic capacity of bone marrow-derived and whole lung CD11c⁺ cells could be inhibited by neuropeptides CGRP, VIP, and Substance P. We then cross-linked these data with the in vivo situation by analyzing DC motility in two different OVA asthma models. Both in the acute and prolonged OVA asthma model altered neuropeptide amounts and DC motility in the airways could be measured. In summary, our data suggest that neuropeptides modulate key features motility and phagocytosis of mouse airway DC. Therefore altered neuropeptide levels in airways during allergic inflammation have impact on regulation of airway immune mechanisms and therefore might contribute to the pathophysiology of asthma.     

Diskussionsbeitrag zur Segmentierung des Cheliceraten-Kopfes

Zusammenfassung Die kritischen Untersuchungen von Weygoldt's Untersuchungen über die Kopf-Entwicklung bei Amblypygi erbringen die gleichen Resultate wie die beiPardosa hortensis (Pross, 1966). Es gibt keine neuen Gesichtspunkte, die zu einer besseren Kenntnis des Kopf-Problems führen würden.Auf der Basis zahlreicher Querschnitte wird das Coelom und seine Korrelationen zum Gehirn der Arachnida diskutiert.

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Contribution to the discussion of head-segmentation of chelicerta

Summary The critical aspects of Weygoldt's researches about the head development of Amblypygi show the same results like those ofPardosa hortensis (Pross, 1966). There are no new viewpoints, which lead to better knowledge about the headproblems.On the basis of numerous cross-sections the coelomic mesoderme and its connections to the brain of Arachnida is discussed.

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Abkürzungen Ch Chelicere - ChC Cheliceren-Coelom - ChG Cheliceren-Ganglion - Chmes Cheliceren-Mesoderm - CLA Cerebral-Lobus-Anlage - CpA Corpora-pedunculata-Anlage - DcC deutocephales Coelom - Dcmes deutocephales Mesoderm - Lab Labrum - Lbmes labrales Mesoderm - 1LV lateraler Teil des Lateral-Vesikels - LV Lateral-Vesikel - LVA Lateral-Vesikel-Anlage - hlfGr halbmondförmige Grube - Mes Mesoderm - mLV medianer Teil des Lateral-Vesikels - Oes Oesophagus - OLiA Überlippen-Anlage - PcC prosocephales Coelom - PcClb labraler Teil des prosocephalen Coeloms - Pcmes prosocephales Mesoderm - Pd Pedipalpen - PdC Pedipalpen-Coelom - PdG Pedipalpen-Ganglion - Pdmes Pedipalpen-Mesoderm - SMA Sehmassen-Anlage - Stom Stomodaeum - ZK Zentralkörper - ZKA Zentralkörper-Anlage     

Adaptive maternal behavioral plasticity and developmental programming mitigate the transgenerational effects of temperature in dung beetles

Phenotypic plasticity allows organisms to cope with rapid environmental change. Yet exactly when during ontogeny plastic responses are elicited, whether plastic responses produced in one generation influence phenotypic variation and fitness in subsequent generations, and the role of plasticity in shaping population divergences, remains overall poorly understood. Here, we use the dung beetle Onthophagus taurus to assess plastic responses to temperature at several life stages bridging three generations and compare these responses across three recently diverged populations. We find that beetles reared at hotter temperatures grow less than those reared at mild temperatures, and that this attenuated growth has transgenerational consequences by reducing offspring size and survival in subsequent generations. However, we also find evidence that plasticity may mitigate these consequences in two ways: 1) mothers modify the temperature of their offspring's developmental environment via behavioral plasticity and 2) in one population, offspring exhibit accelerated growth when exposed to hot temperatures during very early development (‘developmental programming’). Lastly, our study reveals that offspring responses to temperature diverged among populations in fewer than 100 generations, possibly in response to range‐specific changes in climatic or social conditions.     

Influence of the margin vegetation on the conservation of aphid biological control in apple orchards

The influence of three margin strip treatments (wildflower strips, grass strips and spontaneous vegetation) adjacent to apple orchards on the biological control of Dysaphis plantaginea Passerini (Hemiptera: Aphididae) was compared during two consecutive years. The wildflower strips provided the highest amount of floral resources. Within the margin strips, hoverflies responded positively to higher resource provisioning whereas ladybird abundance did not differ between strip treatments. Within the orchards, the presence of parasitoids, hoverflies, and ladybirds in aphid colonies and the predation of sentinel aphids were not significantly affected by the adjacent strip treatments. The number of natural enemies observed in aphid colonies was mainly driven by aphid number. Aphid numbers were higher close to the margin strips suggesting that aphid colonization from orchard edges may counteract the positive effect of wildflower strips on natural enemy abundance and on a reduction of aphid infestation. The results confirm the positive influence of floral resource provisioning by wildflower strips on the conservation of aphid natural enemies, but also suggest that effects of wildflower strips on aphid regulation inside orchards are not very strong compared with spontaneous vegetation naturally occurring in the margins.     

Recombination Losses Above and Below the Transport Percolation Threshold in Bulk Heterojunction Organic Solar Cells

Achieving the highest power conversion efficiencies in bulk heterojunction organic solar cells requires a morphology that delivers electron and hole percolation pathways for optimized transport, plus sufficient donor:acceptor contact area for near unity charge transfer state formation. This is a significant structural challenge, particularly in semiconducting polymer:fullerene systems. This balancing act in the model high efficiency PTB7:PC70BM blend is studied by tuning the donor:acceptor ratio, with a view to understanding the recombination loss mechanisms above and below the fullerene transport percolation threshold. The internal quantum efficiency is found to be strongly correlated to the slower carrier mobility in agreement with other recent studies. Furthermore, second‐order recombination losses dominate the shape of the current density–voltage curve in efficient blend combinations, where the fullerene phase is percolated. However, below the charge transport percolation threshold, there is an electric‐field dependence of first‐order losses, which includes electric‐field‐dependent photogeneration. In the intermediate regime, the fill factor appears to be limited by both first‐ and second‐order losses. These findings provide additional basic understanding of the interplay between the bulk heterojunction morphology and the order of recombination in organic solar cells. They also shed light on the limitations of widely used transport models below the percolation threshold.     

Studying the effects of heavy metal on chlorophyll and sugar in one year-old seedlings organs of Acer velutinum specie

Pollution is one of the most important factors inhibiting growth in the environment; therefore the effects of zinc pollution were studied in Acer velutinum specie. Two years old seedlings of Acer velutinum specie were prepared from nursery, the concentrations of zero and one hundred and thirty mg per liter of zinc chloride solution were added to the soil of seedlings pots after calculating and after passing a three-month period of seedling growth, the plant organs were removed, then the amount of zinc concentration in the samples was determined and data were analyzed. The results of the analysis showed that the highest amount of accumulation on the stem, root and soil in treatment concentrations is 87.75, 65.68 and 24.78 mg per kg and accumulation of zinc in total chlorophyll and sugar in treatment concentrations is 4.61 and 0.6028 mg per g, respectively, and accordingly Acer velutinum specie is suitable for refinement of soils contaminated with zinc.