Human–felid conflict as a further handicap to the conservation of the critically endangered Iberian lynx

Most studies on felid depredation of livestock have focused on big cats, and little attention has been paid to this type of conflict in smaller species. The medium-sized Iberian lynx (Lynx pardinus) is not thought to be affected by conflict with humans. However, parallel to an increase in the range of the Iberian lynx in Andújar-Cardeña, an increased incidence of Iberian lynx attacks on livestock has been recorded. A 6-year overview of Iberian lynx predation on livestock in this population shows a total of 40 attacks involving 716 kills (31 attacks on poultry and nine on sheep). Although the majority of these attacks (78 %) were carried out against poultry, sheep depredation resulted in higher economic losses, mainly in extensive flocks (4.6 times more than semi-intensive flocks). An effective compensation program has been implemented in order to mitigate the consequences of the human–lynx conflict in this area. Given that this sort of conflict could become an acute impediment to future conservation of the most endangered felid, managers should anticipate and prevent the potential conflicts that could arise as Iberian lynx colonizes more developed areas.     

Resistance of grapevine to the erineum strain of Colomerus vitis (Acari: Eriophyidae) in western Iran and its correlation with plant features

The interaction of grape erineum mite (GEM), Colomerus vitis Pagenstecher (Acari: Eriophyidae), with grape was investigated in the laboratory. We studied some plant morphological biochemical features potentially related to vine resistance/tolerance of eight native grapevine cultivars, extensively cultivated in western Iran, and two non-native cultivars. Free-choice experiments indicated that the cultivars Shahani, Flame seedless and Yaghuti were colonized by lower levels of GEM, whereas Muscat Gordo, Gazne and White Thompson seedless hosted denser populations. These differences between cultivars may be due to differential attractiveness to GEM, possibly associated with plant biochemical and morphological traits. In no-choice assays with six grapevine cultivars, mite population development and some cultivar features were assessed. Mite populations grew fastest on Gazne and Muscat Gordo, and slowest on Yaghuti and Shahani. The degree of mite infestation was associated with reduction of leaf area, increase of leaf weight, shortening of shoots and more numerous erinea: these features were larger on the most infested Gazne, whereas morphological features of Shahani and Yaghuti were scarcely affected by GEM infestation. Also trichome type and density of the assayed cultivars appeared to be related to mite density: the most infested cultivars (Gazne and Muscat Gordo) displayed higher ranks of blade and vein hairs and lower ranks of blade and vein bristles and domatia. No correlation was found between mite density and leaf thickness of mature leaves. The amount of leaf waxes was highest in Shahani and Yaghuti, which displayed the lowest mite density, the fewest erinea and the largest leaves. Carbohydrate amount of uninfested leaves was lowest on the least infested Shahani and highest on the most infested Gazne; phenols increased in leaves of Shahani and decreased in those of Gazne after mite infestation. Finally, cultivars also appeared to influence some morphological traits of the mites: larger specimens were detected on White Thompson seedless, Flame seedless and Gazne, whereas smaller mites were found on leaves of the less infested Yaghuti and Shahani. These results indicate that leaf hairiness, leaf wax and carbohydrate contents may be useful tools for a preliminary screening among vine cultivars and help predict resistance/tolerance to GEM. Shahani and Yaghuti seem quite promising for developing grape resistance programs against GEM in western Iran.     

Diurnal variations of nitrate reductase activity and stability in barley leaves

Diurnal variations of nitrate reductase (NR) activity and stability have been studied in leaves of barley seedlings ( Hordeum vulgare L. cv. Herta) grown in an 8 h light/16 h darkness regime. Stability (decay) of NR was tested both in the extracts and in the plants. In the morning, when the plants were transferred to light, NR activity increased rapidly during the first hour and then remained constant. After the photoperiod, activity decreased rapidly during the first hour of darkness and then remained fairly constant during the rest of the dark period. The high NR activity during the photoperiod was associated with low NR stability both in the extracts and in the plants. On the other hand the low NR activity during the dark period was associated with high stability in the extracts and in the plants.     

A statistical analysis of the three-fold evolution of genomic compression through frame overlaps in prokaryotes

Background  

Among microbial genomes, genetic information is frequently compressed, exploiting redundancies in the genetic code in order to store information in overlapping genes. We investigate the length, phase and orientation properties of overlap in 58 prokaryotic species evaluating neutral and selective mechanisms of evolution.     

Methylation of protein phosphatase 2A—Influence of regulators and environmental stress factors

Protein phosphatase 2A catalytic subunit (PP2A‐C) has a terminal leucine subjected to methylation, a regulatory mechanism conserved from yeast to mammals and plants. Two enzymes, LCMT1 and PME1, methylate and demethylate PP2A‐C, respectively. The physiological importance of these posttranslational modifications is still enigmatic. We investigated these processes in Arabidopsis thaliana by mutant phenotyping, by global expression analysis, and by monitoring methylation status of PP2A‐C under different environmental conditions. The lcmt1 mutant, possessing essentially only unmethylated PP2A‐C, had less dense rosettes, and earlier flowering than wild type (WT). The pme1 mutant, with 30% reduction in unmethylated PP2A‐C, was phenotypically comparable with WT. Approximately 200 overlapping genes were twofold upregulated, and 200 overlapping genes were twofold downregulated in both lcmt1 and pme1 relative to WT. Differences between the 2 mutants were also striking; 97 genes were twofold upregulated in pme1 compared with lcmt1, indicating that PME1 acts as a negative regulator for these genes. Analysis of enriched GO terms revealed categories of both abiotic and biotic stress genes. Furthermore, methylation status of PP2A‐C was influenced by environmental stress, especially by hypoxia and salt stress, which led to increased levels of unmethylated PP2A‐C, and highlights the importance of PP2A‐C methylation/demethylation in environmental responses.     

Multi-Scale Analysis of the European Airspace Using Network Community Detection

We show that the European airspace can be represented as a multi-scale traffic network whose nodes are airports, sectors, or navigation points and links are defined and weighted according to the traffic of flights between the nodes. By using a unique database of the air traffic in the European airspace, we investigate the architecture of these networks with a special emphasis on their community structure. We propose that unsupervised network community detection algorithms can be used to monitor the current use of the airspace and improve it by guiding the design of new ones. Specifically, we compare the performance of several community detection algorithms, both with fixed and variable resolution, and also by using a null model which takes into account the spatial distance between nodes, and we discuss their ability to find communities that could be used to define new control units of the airspace.     

NADH substrate inhibition and enhanced thermal stability of higher plant nitrate reductase immobilized via a monoclonal antibody

The molecular basis of light-induced circadian rhythms of higher plant NADH:nitrate reductase (EC 1.6.6.1) activity is presently not understood. We have investigated whether the regulatory properties of NADH:nitrate reductase would allow oscillatory or related dynamic behavior. We report here the first example of NADH substrate inhibition of higher plant nitrate reductase in solution and for an immobilized enzyme using a novel immobilization technique with a monoclonal antibody. According to current theories on chemical oscillatory reactions, substrate inhibition will allow bistable and oscillatory behavior when the substrate-enzyme reaction is carried out in an open system. We also found a significant enhanced thermal stability of the immobilized enzyme.     

Structure of 4-diphosphocytidyl-2-C- methylerythritol synthetase involved in mevalonate- independent isoprenoid biosynthesis.

The YgbP protein of Escherichia coli encodes the enzyme 4-diphosphocytidyl-2-C-methylerythritol (CDP-ME) synthetase, a member of the cytidyltransferase family of enzymes. CDP-ME is an intermediate in the mevalonate-independent pathway for isoprenoid biosynthesis in a number of prokaryotic organisms, algae, the plant plastids and the malaria parasite. Because vertebrates synthesize isoprenoid precursors using a mevalonate pathway, CDP-ME synthetase and other enzymes of the mevalonate-independent pathway for isoprenoid production represent attractive targets for the structure-based design of selective antibacterial, herbicidal and antimalarial drugs. The high-resolution structures of E. coli CDP-ME synthetase in the apo form and complexed with both CTP-Mg2+ and CDP-ME-Mg2+ reveal the stereochemical principles underlying both substrate and product recognition as well as catalysis in CDP-ME synthetase. Moreover, these complexes represent the first experimental structures for any cytidyltransferase with both substrates and products bound.