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.     

Induction, by adriamycin and mitomycin C, of modifications in lipid composition, size distribution, membrane fluidity and permeability of cultured RDM4 lymphoma cells

Adriamycin and mitomycin C were previously found to modulate the sensitivity of lymphoma cells to lysis by certain effectors of immunity and this modulation was dependent on drug concentration. In the present studies, RDM4 lymphoma cells were treated with different concentrations of the two drugs for 24 h in culture. These treatments resulted in changes in the lipid composition, membrane fluidity, cell size distribution, and permeability to 51CrO4, Trypan blue, Acridine orange and trimethylaminodiphenylhexatriene (TMA-DPH) of the cells. Changes in some of these parameters, as a function of drug concentration, resulted in dose-response curves which were bell-like shaped, hence paradoxical similarities between non-drug-treated cells and cells treated with higher drug concentrations were observed.     

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.

     

A satellite cell mitogen from crushed adult muscle

Single fiber-satellite cell units from skeletal muscle of adult rats were used to study the regulation of satellite cell proliferation. The satellite cells remained quiescent during culture in serum-containing medium but could be induced to enter the cell cycle by exposure to a saline extract of crushed adult muscle. The activity in the extract has a molecular weight greater than 30K and is heat and trypsin sensitive. The mitogenic activity does not result from transferrin. Little or no activity was obtained from crushed extracts of heterologous tissues. Proliferation of myogenic cells from rat embryos was also stimulated by the muscle mitogen but growth of muscle fibroblasts was not enhanced. The time response of satellite cell proliferation after exposure to the muscle mitogen showed that the cells enter DNA synthesis after a lag period of 18 hr and proliferate with a generation time of 12 hr. This confirms that satellite cells in adult muscle are in G0, or an extended G1. The mitogen is also effective in stimulating muscle growth and myoblast fusion in vivo when injected into 1-week-old rat pups. These experiments suggest that muscle regeneration is initiated by the release of an endogenous mitogen from traumatized muscle.     

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.     

Impact of Concentration Ratio on the Formation and Stability of Emulsions Stabilized by Quillaja Saponin – Sodium Caseinate Mixtures

Food Biophysics - The stabilization of interfaces with mixed emulsifiers composed of natural ingredients is of increasing interest in order to modulate stability of food colloids. To this purpose,...     

Isolation, characterization, and expression of cDNA encoding a rat liver endoplasmic reticulum alpha-mannosidase

We have isolated a cDNA encoding an endoplasmic reticulum alpha-mannosidase, an asparagine-linked oligosaccharide processing enzyme, from a rat liver lambda gt11 library. Two degenerate oligonucleotides, based on amino acid sequence data from the purified enzyme, were used as primers in the polymerase chain reaction with liver cDNA as a template to generate an unambiguous cDNA probe. The cDNA fragment (524 base pair) obtained was then used to isolate cDNA clones by hybridization. We isolated two overlapping clones which were used to construct a full-length cDNA of 3392 base pairs. A single open reading frame of 1040 amino acids encodes a protein with a molecular mass of 116 kilodaltons containing the six known peptide sequences. The deduced amino acid sequence revealed no classical signal sequence or membrane-spanning domain. The alpha-mannosidase encoding cDNA can be expressed transiently in COS cells using the mammalian expression vector pXM, causing a 400-fold increase in alpha-mannosidase activity as well as a dramatic increase in immunoreactive polypeptide. The rat liver endoplasmic reticulum alpha-mannosidase bears striking homology to the vacuolar alpha-mannosidase from Saccharomyces cerevisiae.     

Biomonitoring of arylamines: haemoglobin adducts of aniline derivatives

Aromatic amines are important intermediates in industrial manufacturing. They are used in a large number of products, such as pesticides, dyes, plastics and pharmaceuticals. The parent arylamines can be metabolically released from these arylamine-based compounds and form DNA and protein adducts after N-oxidation to N-hydroxy arylamines. Aromatic amine derivatives, including the industrial intermediates acetoacetanilide, acetoacet-m-xylidide and N-ethylaniline, were examined for their ability to form Hb adducts in rats as potential biomarkers of exposure. The haemoglobin binding indices (HBI=binding [mmol mol^-1 Hb]/dose [mmol kg^-1 body weight]) of the arylamines were determined 24 h after oral administration to female Wistar rats. The precipitated haemoglobin was dissolved in 0.1 M sodium hydroxide in the presence of internal standards. After hexane extraction the released arylamines were analysed by gas chromatography-mass spectrometry (GC-MS). For aniline released from acetoacetanilide an HBI of 15 and for 2,4-dimethylaniline released from acetoacet-m-xylidide an HBI of 0.129 were determined. The HBIof aniline released from N-ethylaniline was 45.     

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.