Albumin affinity tags increase peptide half-life in vivo

Small organic molecules that bind tightly to serum albumin were applied to the amino terminus of an anticoagulant peptide in an effort to increase its protein binding in vivo. The tagged peptides were evaluated for their ability to be retained on liquid chromatographic columns with serum albumins incorporated into the stationary phase. Those which demonstrated significant affinity were administered intravenously to rabbits and found to have significantly increased plasma half-lives. Novel affinity tags were identified by appending a focused library of compounds to a model tetrapeptide and evaluating the resulting compounds' ability to bind to the serum albumin columns. The most promising were synthesized as the full length peptides and again evaluated in vivo. They were found to have still longer half-lives than the first generation compounds.     

Spatially-Explicit Estimation of Geographical Representation in Large-Scale Species Distribution Datasets

Much ecological research relies on existing multispecies distribution datasets. Such datasets, however, can vary considerably in quality, extent, resolution or taxonomic coverage. We provide a framework for a spatially-explicit evaluation of geographical representation within large-scale species distribution datasets, using the comparison of an occurrence atlas with a range atlas dataset as a working example. Specifically, we compared occurrence maps for 3773 taxa from the widely-used Atlas Florae Europaeae (AFE) with digitised range maps for 2049 taxa of the lesser-known Atlas of North European Vascular Plants. We calculated the level of agreement at a 50-km spatial resolution using average latitudinal and longitudinal species range, and area of occupancy. Agreement in species distribution was calculated and mapped using Jaccard similarity index and a reduced major axis (RMA) regression analysis of species richness between the entire atlases (5221 taxa in total) and between co-occurring species (601 taxa). We found no difference in distribution ranges or in the area of occupancy frequency distribution, indicating that atlases were sufficiently overlapping for a valid comparison. The similarity index map showed high levels of agreement for central, western, and northern Europe. The RMA regression confirmed that geographical representation of AFE was low in areas with a sparse data recording history (e.g., Russia, Belarus and the Ukraine). For co-occurring species in south-eastern Europe, however, the Atlas of North European Vascular Plants showed remarkably higher richness estimations. Geographical representation of atlas data can be much more heterogeneous than often assumed. Level of agreement between datasets can be used to evaluate geographical representation within datasets. Merging atlases into a single dataset is worthwhile in spite of methodological differences, and helps to fill gaps in our knowledge of species distribution ranges. Species distribution dataset mergers, such as the one exemplified here, can serve as a baseline towards comprehensive species distribution datasets.     

Emergence activity at hibernacula differs among four bat species affected by white‐nose syndrome

Prior to the introduction of white‐nose syndrome (WNS) to North America, temperate bats were thought to remain within hibernacula throughout most of the winter. However, recent research has shown that bats in the southeastern United States emerge regularly from hibernation and are active on the landscape, regardless of their WNS status. The relationship between winter activity and susceptibility to WNS has yet to be explored but warrants attention, as it may enable managers to implement targeted management for WNS‐affected species. We investigated this relationship by implanting 1346 passive integrated transponder (PIT) tags in four species that vary in their susceptibility to WNS. Based on PIT‐tag detections, three species entered hibernation from late October to early November. Bats were active at hibernacula entrances on days when midpoint temperatures ranged from −1.94 to 22.78°C (mean midpoint temperature = 8.70 ± 0.33°C). Eastern small‐footed bats (Myotis leibii), a species with low susceptibility to WNS, were active throughout winter, with a significant decrease in activity in mid‐hibernation (December 16 to February 15). Tricolored bats (Perimyotis subflavus), a species that is highly susceptible to WNS, exhibited an increase in activity beginning in mid‐hibernation and extending through late hibernation (February 16 to March 31). Indiana bats (M. sodalis), a species determined to have a medium–high susceptibility to WNS, remained on the landscape into early hibernation (November 1 to December 15), after which we did not record any again until the latter portion of mid‐hibernation. Finally, gray bats (M. grisescens), another species with low susceptibility to WNS, maintained low but regular levels of activity throughout winter. Given these results, we determined that emergence activity from hibernacula during winter is highly variable among bat species and our data will assist wildlife managers to make informed decisions regarding the timing of implementation of species‐specific conservation actions.     

Multiple stressors on biotic interactions: how climate change and alien species interact to affect pollination

Global change may substantially affect biodiversity and ecosystem functioning but little is known about its effects on essential biotic interactions. Since different environmental drivers rarely act in isolation it is important to consider interactive effects. Here, we focus on how two key drivers of anthropogenic environmental change, climate change and the introduction of alien species, affect plant–pollinator interactions. Based on a literature survey we identify climatically sensitive aspects of species interactions, assess potential effects of climate change on these mechanisms, and derive hypotheses that may form the basis of future research. We find that both climate change and alien species will ultimately lead to the creation of novel communities. In these communities certain interactions may no longer occur while there will also be potential for the emergence of new relationships. Alien species can both partly compensate for the often negative effects of climate change but also amplify them in some cases. Since potential positive effects are often restricted to generalist interactions among species, climate change and alien species in combination can result in significant threats to more specialist interactions involving native species.     

Formation and succession of alvar communities in the Baltic land uplift area

Calciphilous plant communities, soil and geomorphology along the gradient of elevation in land uplift area in the coast of western Estonia were described. In grazed areas, species rich alvar grassland is a final stage in successional sere. The differences in site history in various points of the transect were reflected by the variability of underlying deposits. When soils with different ages but having similar parent material were compared, some successional trends (decrease of the content of Ca, increase of the content of P and humus supply) became evident. Species composition of plant communities was determined mainly by local ecological conditions (moisture level, soil pH, also grazing) at any particular site. Differences between communities of the same association but with different successional age were negligible.     

Effect of arbuscular mycorrhiza on inter- and intraspecific competition of two grassland species

We were interested in the role of arbuscular mycorrhiza (AM) in the competition between plants of different sizes. A pot experiment of factorial design was established, in which AM root colonization and competition were used as treatments. Five-week-old Prunella vulgaris seedlings were chosen as target plants (i.e. plants whose response to competition was studied) and the following (13 replicates of each) were used as neighbours: (1) a large, 10-week-old P. vulgaris, (2) two P. vulgaris seedlings, and (3) a large, 10-week-old Fragaria vesca. In the experiment where small neighbours were grown together with small target plants, competition did not reduce target plant weight significantly, compared to the other two treatments. The competitive effects of large neighbours were significant, regardless of species (both older neighbours reduced the weights of target plants similarly), but there was a clear difference between intra- and interspecific competition when plants were mycorrhizal. In intraspecific competition with a large neighbour, the target plant shoot weight was reduced 24% when inoculated with AM. Thus, AM amplified rather than balanced intraspecific competition. In interspecific competition with old F. vesca, the shoot weights of target plants were 22% greater when inoculated with AM than when non-mycorrhizal. The results showed that, for given soil condition, AM might increase species diversity by increasing competitive intraspecific suppression and decreasing the interspecific suppression of small plants by larger neighbours.     

Interspecific competition and arbuscular mycorrhiza: Importance for the coexistence of two calcareous grassland species

Two naturally coexisting grassland species—Centaurea jacea (often predominating) andFragaria vesca (subordinate) were grown together in a pot experiment of factorial design, where competition and arbuscular mycorrhiza (AM) inoculation were used as treatments. The effects of competition were one-sided, i.e. the mass ofF. vesca decreased relatively more than that ofC. jacea as a result of competition. The root and total mass ofC. jacea increased with AM inoculation whileF. vesca did not respond. The mass difference betweenC. jacea andF. vesca in a particular pot increased when plants were mycorrhizal, mostly due to the mass increase ofC. jaceae. This can be explained by the differential response of these species to AM. We did not find any indirect indication of the interplant transfer of resources. The results of this experiment show the more unbalanced competition (larger differences in biomass) resulting from AM infection of plants. *** DIRECT SUPPORT *** A02DO006 00010     

Selection of source material for introduction of the locally rare and threatened fern species Asplenium septentrionale

Background: Forked spleenwort, Asplenium septentrionale, is a mainly petrophilous fern species in European mountains and rare on acidic siliceous rocks in lowland areas of the continent, where habitats are fragmented and populations isolated. In Estonia, the single extant population is very small, occupies a restricted area and is threatened by human disturbances. An introduction project of the species was prepared to form new populations in new protected sites using ex-situ propagated young sporophytes as transplantation material.

Aims: To obtain data on the species recruitment population biology and provide context information for selecting donor plant material.

Methods: We sampled three regional/local donor populations. First, we carried out a laboratory breeding experiment to evaluate the populations’ ability for intra-gametophytic selfing. Second, to estimate differences in fitness of offspring among the populations, we grew young sporophyte plants in a pot experiment under controlled conditions in a common garden.

Results: The Estonian population showed very high capacity (90%) for intra-gametophytic selfing, as well as high rate of sporophytic mortality (83%), but the rates are comparable to one of the reference populations in Finland. However, plants of Estonian population were smaller.

Conclusions: The Estonian population may represent a unique pre-adapted or locally adapted genotype; therefore, it needs more efficient protection in its present location. Planting material for introduction should be collected from the local population, as the best locally adapted. Only in the risk of severe environmental change and of extinction, several neighbouring populations could be pooled to maximise genetic diversity.     

Accuracy and selection success in yield trial analyses

Summary Yield trials serve research purposes of estimation and selection. Order statistics are used here to quantify the successes or problems to be expected in selection tasks commonly encountered in breeding and agronomy. Greater accuracy of yield estimates implies greater selection success. A New York soybean yield trial serves as a specific example. The Additive Main effects and Multiplicative Interaction (AMMI) statistical model is used to increase the accuracy of these soybean yield estimates, thereby increasing the probability of successfully selecting, on the basis of the empirical yield data, that genotype which has the maximum true mean. The statistical strategy for increasing accuracy is extremely cost effective relative to the alternative strategy of increasing the number of replications. Better selections increase the speed and effectiveness of breeding programs, and increase the reliability of variety recommendations. Selection tasks are frequently more difficult than may be suspected.This research was supported by the Rhizobotany Project of the USDA-ARS