A novel fluorescent pH probe for expression in plants

Background  

The pH is an important parameter controlling many metabolic and signalling pathways in living cells. Recombinant fluorescent pH indicators (pHluorins) have come into vogue for monitoring cellular pH. They are derived from the most popular Aequorea victoria GFP (Av-GFP). Here, we present a novel fluorescent pH reporter protein from the orange seapen Ptilosarcus gurneyi (Pt-GFP) and compare its properties with pHluorins for expression and use in plants.     

Connectedness of habitat fragments boosts conservation benefits for butterflies,but only in landscapes with little cropland

Landscape Ecology - Global change pressures (GCPs) imperil species and associated ecosystem functions, but studies investigating interactions of landscape-scale pressures remain scarce. Loss of...     

An agent-based approach to modeling impacts of agricultural policy on land use, biodiversity and ecosystem services

We present extensions to the agent-based agricultural policy simulator (AgriPoliS) model that make it possible to simulate the consequences of agricultural policy reform on farmers?? land use decisions and concomitant impacts on landscape mosaic, biodiversity and ecosystem services in a real agricultural region. An observed population of farms is modelled as a multi-agent system where individual farm-agent behaviour and their interactions??principally competition for land??are defined through an optimization framework with land use and landscape impacts resulting as emergent properties of the system. The model is calibrated to real data on the farms and the landscape to be studied. We illustrate the utility of the model by evaluating the potential impacts of three alternative frameworks for the European Union Common Agricultural Policy (CAP) on landscape values in two marginal agricultural regions. Mosaic value was found to be sensitive to the choice of policy scheme in one of the landscapes, whereas significant trade-offs were shown to occur in terms of species richness by habitat and species composition at the landscape scale in both regions. The relationship between food production and other ecosystem services was found to be multifaceted. Thus illustrating the difficulty of achieving landscape goals in a particular region with simple or general land management rules (such as the current rules attached to CAPs direct payments). Given the scarcity of funding for conservation, the level and conditions for allocating direct payments are, potentially, of great importance for preserving landscape values in marginal agricultural regions (subject to levels of other support).     

UNILATERAL COMPLETE OBSTRUCTION OF THE PRIMARY BRONCHUS IN TWO JUVENILE MACAWS (ARA SPP.)

Two juvenile macaws presented independently with clinical signs associated with respiratory signs that included coughing, wheezing, and increased respiratory effort and rate. Whole body radiographis were obtained from one patient, and were considered normal. Computed tomography identified unilateral complete primary bronchial obstruction in both cases. Tracheoscopy was performed in both cases and identified a partial obstruction of the syrinx in one case. Biopsy samples collected during tracheoscopy were submitted for microbial culture. Aspergillus spp. was isolated and treatment was unsuccessful for this macaw. The second case was euthanized upon diagnosis. In both cases, a complete necropsy confirmed the primary bronchial obstruction and fungal organisms were identified, consistent with Aspergillus spp. As demonstrated by these two cases, radiography and tracheoscopy do not allow for the diagnosis of primary bronchial obstruction in birds. Therefore, a computed tomography scan is recommended to accurately diagnose this condition in avian patients.     

REMI (Restriction Enzyme Mediated Integration) and its Impact on the Isolation of Pathogenicity Genes in Fungi Attacking Plants

Development of molecular techniques for phytopathogenic fungi aims at the identification of fungal genes whose products are essential for successful infection of the host plant. Initial approaches have relied on isolating candidate genes and generating null-mutations by homologous recombination. Unfortunately, the results of this strategy have not been overly successful. This has led to a search for alternatives which allow an unbiased identification of pathogenicity genes. One method, which has proved successful in several systems, is a tagging mutagenesis procedure termed restriction enzyme mediated integration (REMI). In this mini-review we describe this procedure and review its features and results of its use when applied to the identification of fungal genes required for disease development in planta.     

Solanum scabrum—a potential source of a coloring plant extract

The objective of this study was to examine the potential of Solanum scabrum to provide a colorant for food. We conducted a field trial with eight accessions from four different sources and recorded both morphological variability and fruit yield differences between accessions. Further, anthocyanin and glucoalkaloid concentrations were determined. The accessions could be assigned to two distinct groups: a leafy vegetable type with toxic fruits used in Africa and a berry type with edible fruits known as Garden Huckleberry in North America, but both types had edible leaves with low glucoalkaloid concentrations. The leafy vegetable type set not much fruit. In contrast, the berry type yielded on average 800–900 g berries per plant with remarkable high anthocyanin concentrations of 8.1–13.9 g kg⁻¹ fresh weight, calculated as petunidin 3-p-(coumaryl-runtinoside)-5-glucoside. Thus, S. scabrum can serve as a source for natural anthocyanin pigments. In particular, two accessions with a high fruit yield were promising candidates as a berry crop. One had the best anthocyanin concentration of the examined material and the other one had a low percentage of unripe berries as a further advantage.     

Elevated CO2 stimulates N2O emissions in permanent grassland

To evaluate climate forcing under increasing atmospheric CO₂ concentrations, feedback effects on greenhouse gases such as nitrous oxide (N₂O) with a high global warming potential should be taken into account. This requires long-term N₂O flux measurements because responses to elevated CO₂ may vary throughout annual courses. Here, we present an almost 9 year long continuous N₂O flux data set from a free air carbon dioxide enrichment (FACE) study on an old, N-limited temperate grassland. Prior to the FACE start, N₂O emissions were not different between plots that were later under ambient (A) and elevated (E) CO₂ treatments, respectively. However, over the entire experimental period (May 1998–December 2006), N₂O emissions more than doubled under elevated CO₂ (0.90 vs. 2.07 kg N₂O-N ha⁻¹ y⁻¹ under A and E, respectively). The strongest stimulation occurred during vegetative growth periods in the summer when soil mineral N concentrations were low. This was surprising because based on literature we had expected the highest stimulation of N₂O emissions due to elevated CO₂ when mineral N concentrations were above background values (e.g. shortly after N application in spring). N₂O emissions under elevated CO₂ were moderately stimulated during late autumn–winter, including freeze–thaw cycles which occurred in the 8th winter of the experiment. Averaged over the entire experiment, the additional N₂O emissions caused by elevated CO₂ equaled 4738 kg CO₂-equivalents ha⁻¹, corresponding to more than half a ton (546 kg) of CO₂ ha⁻¹ which has to be sequestered annually to balance the CO₂-induced N₂O emissions. Without a concomitant increase in C sequestration under rising atmospheric CO₂ concentrations, temperate grasslands may be converted into greenhouse gas sources by a positive feedback on N₂O emissions. Our results underline the need to include continuous N₂O flux measurements in ecosystem-scale CO₂ enrichment experiments.