Growth variability of the Greenland smoothcockle Serripes groenlandicus (Brugiere 1789) affected by glacier induced changes in the Kongsfjorden ecosystem

Climate change forces retreat of Arctic glaciers and release of increased quantities of melt water and terrigenous material into coastal habitats of the Arctic such as the Kongsfjorden Ecosystem. The effect of this glacier induced physical parameters on growth and abundance of the Greenland smoothcockle (Serripes groenlandicus, Bruguière 1798) were determined. Along Kongsfjorden, at five stations with increasing distance to the Kongsbreen glacier, specimen of the cockle were collected and physical parameters were measured. Effects on growth of S. groenlandicus were analyzed by measuring variability of annual increments obtained from cockles’ thin section. Towards the glacier front temperature and Chlorophyll a content of the water column decreased, whereas total suspended matter and sedimentation rates increased. Regression analysis revealed lowest growth rate at the station close to Kongsbreen. Average standard growth index (SGI) of S. groenlandicus was lowest at this station (-0.4884±0.1763 95%CI), highest at Ny Alesund (0.1523±0.1158 95%CI), and decreased towards the mouth of Kongsfjorden (-0.0217±0.0718 95%CI and -0.1310±0.0759 95%CI, respectively at the two outer stations). Multi regression analysis revealed a strong relationship between average SGI and temperature (P<0.001, R²=0.75) as well as total sedimented material (P=0.018, R²=0.80)

Karyotype Variability and Inter-Population Genomic Differences in Freshwater Ostracods (Crustacea) Showing Geographical Parthenogenesis

Transitions from sexual to asexual reproduction are often associated with polyploidy and increased chromosomal plasticity in asexuals. We investigated chromosomes in the freshwater ostracod species Eucypris virens (Jurine, 1820), where sexual, asexual and mixed populations can be found. Our initial karyotyping of multiple populations from Europe and North Africa, both sexual and asexual, revealed a striking variability in chromosome numbers. This would suggest that chromosomal changes are likely to be accelerated in asexuals because the constraints of meiosis are removed. Hence, we employed comparative genomic hybridization (CGH) within and among sexual and asexual populations to get insights into E. virens genome arrangements. CGH disclosed substantial genomic imbalances among the populations analyzed, and three patterns of genome arrangement between these populations: 1. Only putative ribosomal DNA (rDNA)-bearing regions were conserved in the two populations compared indicating a high sequence divergence between these populations. This pattern is comparable with our findings at the interspecies level of comparison;2. Chromosomal regions were shared by both populations to a varying extent with a distinct copy number variation in pericentromeric and presumable rDNA-bearing regions. This indicates a different rate of evolution in repetitive sequences;3. A mosaic pattern of distribution of genomic material that can be explained as non-reciprocal genetic introgression and evidence of a hybrid origin of these individuals. We show an overall increased chromosomal dynamics in E. virens that is complementary with available phylogenetic and population genetic data reporting highly differentiated diploid sexual and asexual lineages with a wide variety of genetic backgrounds

Exploratorial Analysis and a Stochastic Model for Humusdisintegration

Ulrich (1984) supposes in the hypothesis of humusdisintegration that the balance between construction and disintegration of humus in european forests is regionally disturbed. He suspects aluminium to build complexes with enzymes preventing the construction in this way. At a couple of sites located in middle Germany the ingredients of the seepage water are monitored. We explore these multivariate data for examining possible influences on the process of humusdisintegration and its temporal evolution. We gain informations about relations and systematical effects in the data and develop a kind of regression model for carbon concentrations also describing the spatial and temporal variability. Especially iron and aluminium are very influential in our model, but interpretations turn out to be rather difficult because of e.g. high correlations between some of the variables. So far our work is the basic step for monitoring the seepage water data by a stochastic model. 1 Introduction During the..

Drifting of workers in nest aggregations of the giant honeybee Apis dorsata

The extent of worker drifting between nests in aggregations of colonies of the giant Asian honeybee Apis dorsata was studied using DNA microsatellites. Four aggregations with three, six, seven and eight colonies were sampled. 1537 workers were genotyped using four loci. Maternity testing was used to separate drifted and natal workers, and to assign drifted individuals to their actual maternal colony. The proportion of drifted workers ranged from 0 to 6.25% with an average of 1.27% (sd = 0.245). No significant differences in rates of drifting were found between the four aggregations. There was also no correlation between the direction of the drift and the position of the nests relative to each other. These results show that in A. dorsata, a bee species that frequently nests in dense aggregations, the extent of forager drifting between colonies can be very low

A scientific note on the mating frequency of Apis dorsata

(without abstract

Systolic Pulmonary Artery Pressure and Cardiovascular Biomarkers—New Non-Invasive Ways to Detect Pulmonary Hypertension in Patients with Severe Aortic Valve Stenosis Undergoing TAVR?

Background: Patients with severe aortic valve stenosis (AS) frequently present with pulmonary hypertension (PH). The gold standard for detection of pulmonary hypertension is right heart catheterization, which is not routinely performed as a preoperative standard in cardiology centers today, neither before surgical valve replacement nor before transcatheter aortic valve replacement (TAVR) procedure. Echocardiographic determination of systolic pulmonary artery pressure (sPAP) provides an opportunity to assess the presence or absence of PH. The aim of the present study was to investigate the extent to which plasma levels of common cardiovascular biomarkers behave in patients with severe AS and an sPAP <40 mmHg in comparison to patients with an sPAP ≥40 mmHg. Methods: 179 patients with echocardiographic evidence of severe AS before TAVR procedure were divided into 2 groups based on sPAP. An sPAP of 40 mmHg was considered the cut-off value, with absence of PH defined by an sPAP <40 mmHg (n = 82) and presence of PH defined by an sPAP ≥40 mmHg (n = 97). Directly before TAVR, a blood sample was drawn from each patient, and plasma concentrations of the cardiovascular biomarkers Soluble Suppression of Tumorigenicity-2 (sST2), Growth/Differentiation of Factor-15 (GDF-15), Heart-Type Fatty-Acid Binding Protein (H-FABP), Insulin Like Growth Factor Binding Protein 2 (IGF-BP2), Soluble Urokinase-Type Plasminogen Activator Receptor (suPAR), Brain Natriuretic Peptide (BNP) and Cardiac Troponin I (cTnI) were determined. Results: Patients with an sPAP ≥40 mmHg had significantly higher sST2 (p = 0.010), GDF-15 (p = 0.005), IGF-BP2 (p = 0.029), suPAR (p = 0.018), BNP (p < 0.001) and cTnI (p = 0.039) plasma levels. Only for H-FABP (p = 0.069), no significant differences were discernible between the two groups. In addition, cut-off values were calculated to predict an sPAP ≥40 mmHg. Significant results were shown with 16045.84 pg/mL for sST2 (p = 0.010), with 1117.54 pg/mL for GDF-15 (p = 0.005), with 107028.43 pg/mL for IGF-BP2 (p = 0.029), with 3782.84 pg/mL for suPAR (p = 0.018), with 2248.00 pg/mL for BNP (p < 0.001) and with 20.50 pg/mL for cTnI (p = 0.002). Conclusions: sPAP as an echocardiographic parameter in combination with supplementary use of cardiovascular biomarkers presented here have the potential to provide more detailed information about the presence or absence of PH in a non-invasive way