Resurvey studies of terricolous bryophytes and lichens indicate a widespread nutrient enrichment in German forests

Questions

Vegetation resurveys, both single studies and meta-analyses, have predominantly been based on vascular plant data while bryophytes and lichens have largely been neglected. Our study aims to fill this gap and addresses the following research questions: has the overall species richness of terricolous bryophytes and lichens in forests changed over time? Which are the winners and losers among single species and ecological species groups? Do the results give a signal of the impact of nutrient enrichment, of changes in the light regime and of climate change?

Location

Deciduous and coniferous forests in Germany.

Methods

We compiled 35 single resurvey data sets, including 1096 plots in total (each sampled twice). The time interval between initial surveys and resurveys ranged from 10 to 65 years. The differences between old and new plots were analysed with respect to the frequency of single species, total species richness, and the absolute and relative numbers of taxa in the species groups. Trend scores of species were related to ecological indicator values to identify the main environmental drivers behind the observed changes.

Results

Total species richness did not systematically change, while pleurocarpous mosses had increased at the expense of acrocarpous mosses and, in coniferous forests, of lichens. Weak changes were generally observed in deciduous forests on base-rich soils. In coniferous forests and in deciduous forests on acid soils, species with high nitrogen demand and high shade tolerance had increased, whereas those being typical for more infertile and open forest sites had decreased. There were trends towards a larger share of taxa with a more oceanic distribution.

Conclusions

The changes in the vegetation of terricolous bryophytes and lichens in the studied forests indicate nutrient enrichment and increasingly shady conditions in forests on acid soils, likely caused by nitrogen deposition and shrub layer closure.     

Search for putative suppressor genes in meningioma: significance of chromosome 22

Summary Cytogenetic and molecular studies of various solid tumors have indicated that a series of different chromosomal regions may be deleted in the tumor genome. Usually, losses of heterozygosity are observed and, from this finding, the presence of specific genes acting as tumor suppressors has been deduced. In particular tumors, however, only a single chromosome site appears to be affected. Therefore, we have carried out a study of human meningioma, investigating 7 such putative suppressor regions by applying twelve site-specific DNA markers. In 6 out of 19 tumors, we exclusively found loss of heterozygosity for markers of the long arm of chromosome 22; none of the tumors showed statistically significant additional allelic losses for the regions 1p, 3p, 5p, 5q, 11p, 13q, 17p. Our data support the long-standing observation that only losses of or within chromosome 22 are associated with the development of meningiomas. Other suppressor regions are apparently not involved.     

PRIME: a graphical interface for integrating genomic/proteomic databases

Data mining, finding and integration of information about proteins of interest, is an essential component in modern biological and biomedical research. Even when focusing on a single organism and only on a small number of proteins, there are often dozens fo data sources containing relevant information. We are developing PRIME, a protein information environment, to serve as a virtual central database which integrates distributed heterogeneous information about proteins (linked by common identifier). PRIME has powerful capabilities to visualize all kinds of protein annotation in specialized views. These views can be displayed side by side at the same time and can be synchronized in order to show simultaneously different aspects of identical proteins. These features allow a quick and comprehensive overview of properties of single proteins or protein sets.     

Physical,chemical and kinetic factors affecting prion infectivity

The mouse-adapted scrapie prion strain RML is one of the most widely used in prion research. The introduction of a cell culture-based assay of RML prions, the scrapie cell assay (SCA) allows more rapid and precise prion titration. A semi-automated version of this assay (ASCA) was applied to explore a range of conditions that might influence the infectivity and properties of RML prions. These include resistance to freeze-thaw procedures; stability to endogenous proteases in brain homogenate despite prolonged exposure to varying temperatures; distribution of infective material between pellet and supernatant after centrifugation, the effect of reducing agents and the influence of detergent additives on the efficiency of infection. Apparent infectivity is increased significantly by interaction with cationic detergents. Importantly, we have also elucidated the relationship between the duration of exposure of cells to RML prions and the transmission of infection. We established that the infection process following contact of cells with RML prions is rapid and followed an exponential time course, implying a single rate-limiting process.     

Comparing aspirations: intercalibration of ecological status concepts across European lakes for littoral diatoms

Eleven European countries participated in an exercise to harmonise diatom-based methods used for status assessment in lakes. Lakes were divided into low, medium and high alkalinity types for this exercise. However, it was not possible to perform a full intercalibration on low alkalinity lakes due to the short gradient and confounding factors. Values of the Trophie Index were computed for all samples in order that national datasets could all be expressed on a common scale. Not all participants had reference sites against which national methods could be standardised and, therefore, a Generalised Linear Modelling approach was used to control the effect of national differences in datasets. This enabled the high/good and good/moderate status boundaries to be expressed on a common scale and for deviations beyond ±0.25 class widths to be identified. Those countries which had relaxed boundaries were required to adjust these to within ±0.25 class widths whilst the intercalibration rules allowed those countries with more stringent boundaries to retain these. Despite biogeographical and typological differences between countries, there was broad agreement on the characteristics of high, good and moderate status diatom assemblages, and the exercise has ensured consistent application of Water Framework Directive assessments around Europe.