Soil‐nutrient availability under a global‐change scenario in a Mediterranean mountain ecosystem

Changes in rainfall availability will alter soil‐nutrient availability under a climate‐change scenario. However, studies have usually analyzed the effect of either drier or wetter soil conditions, despite the fact that both possibilities will coexist in many climatic regions of the world. Furthermore, its effect may vary across the different habitats of the ecosystem. We experimentally investigated the effect of three contrasting climatic scenarios on different carbon (C), nitrogen (N), and phosphorus (P) fractions in soil and microbial compartments among three characteristic habitats in a Mediterranean‐type ecosystem: forest, shrubland, and open areas. The climatic scenarios were dry summers, according to the 30% summer rainfall reduction projected in the Mediterranean; wet summer, simulating summer storms to reach the maximum historical records in the study area; and current climatic conditions (control). Sampling was replicated during two seasons (spring and summer) and 2 years. The climatic scenario did not affect the nutrient content in the litter layer. However, soil and microbial nutrients varied among seasons, habitats, and climatic scenarios. Soil‐nutrient fractions increased with lower soil‐moisture conditions (dry scenario and summer), whereas microbial nutrients increased under the wet summer scenario and spring. This pattern was consistent both studied years, although it was modulated by habitat, differences being lower with denser plant cover. Holm oak seedlings, used as live control of the experiment, tended to increase their N and P content (although not significantly) with water availability. Thus, the results support the idea that higher rainfall boosts microbial and plant‐nutrient uptake, and hence nutrient cycling. By contrast, a rainfall reduction leads to an accumulation of nutrients in the soil, increasing the risk of nutrient loss by leaching or erosion. These results show that the projected climate change will have significant effects on nutrient cycles, and therefore will have important implications on the ecosystem functioning.     

Effects of age,territoriality and breeding on survival of Bonelli’s Eagle Aquila fasciata

Survival typically contributes most to population trends in long‐lived birds and its accurate estimation is therefore vital for population management and conservation. We evaluated the effects of age, territoriality and reproduction on survival in Bonelli’s Eagle Aquila fasciata through multistate capture‐mark‐recapture analyses on a long‐term dataset. Monitoring was carried out in southeast France (1990–2008) and involved the surveying of territorial Eagles, the marking of fledged chicks, and the recording of resightings and recoveries of marked non‐territorial and territorial birds. Survival improved with age, but territoriality was not retained in the best model; yearly survival was estimated at 0.479 for fledglings (to 1 year of age), 0.570 for 1‐ and 2‐year‐olds, and 0.870 for 3‐year‐old and older individuals. The second best model supported a further increase in survival from 3‐year‐olds (0.821) to older individuals (0.880). In the third best supported model, territoriality enhanced survival, but only in 2‐year‐olds (0.632 vs. 0.562 for non‐territorial). We found no correlation between the previous breeding stage and future survival, consistent with the long lifespan of the study species. Nevertheless, 4‐year‐old and older successful breeders were more likely to breed the following year than failed adult breeders (0.869 vs. 0.582), suggesting that the cost of reproduction is small in comparison with the variation in quality among individuals or their territories.     

A new Late Jurassic turtle from Spain: phylogenetic implications,taphonomy and palaeoecology

Abstract: The Jurassic was an important period in the evolution of Testudinata and encompasses the origin of many clades, and this is especially true of Jurassic turtles from Western Europe. A new genus and species of Late Jurassic turtle, Hispaniachelys prebetica gen. et sp. nov. from the upper Oxfordian of the Prebetic (Southern Spain), is described on the basis of postcranial material. The specimen is the only known tetrapod from the Mesozoic of the Prebetic and the oldest turtle from southern Europe. A mosaic of characters indicates this is a new genus: it displays basal features including dorsal epiplastral processes/reduced cleithra, no medial contact of the extragulars and a long first thoracic rib, alongside derived characters including an absence of mesoplastra and the vertebral 3/4 sulcus crossing neural 5. The phylogenetic position of the new taxon is hard to resolve, and it might be either a paracryptodire or a basal testudine, but it is distinct from Plesiochelys. A complex taphonomic history is shown by a range of overlying grazing traces and bioerosion on the carapace. The carapace was subsequently overturned and buried ventrally up, terminating grazing activity, and was then bored by sponges before final burial. Scanning electron microscopy reveals phosphatic microspheroids associated with bacterial decay in the vascular cavities of the cancellous bone, suggesting the carapace may have acted as a closed microenvironment in which decay‐derived authigenic minerals formed.     

Statistical optimization of medium components for the production of biosurfactant by Bacillus licheniformis K51

The nutritional medium requirement for biosurfactant production by Bacillus licheniformis K51 was optimized. The important medium components, identified by the initial screening method of Plackett-Burman, were H3PO4, CaCl2, H3BO3, and Na-EDTA. Box-Behnken response surface methodology was applied to further optimize biosurfactant production. The optimal concentrations for higher production of biosurfactants were (g/l): glucose, 1.1; NaNO3, 4.4; MgSO4 x 7H2O, 0.8; KCl, 0.4; CaCl2, 0.27; H3PO4, 1.0 ml/l; and trace elements (mg/l): H3BO3, 0.25; CuSO4, 0.6; MnSO4, 2.2; Na2MoO4, 0.5; ZnSO4, 6.0; FeSO4, 8.0; CoCl2, 1.0; and Na-EDTA, 30.0. Using this statistical optimization method, the relative biosurfactant yield as critical micelle dilution (CMD) was increased from 10x to 105x, which is ten times higher than the non-optimized rich medium.     

More than multiple introductions: Multiple taxa contribute to the genesis of the invasive California’s wild artichoke thistle

The history of some invasive species is so complex that their origins can be difficult to determine. One example of such invasive species is the California invasive known as “wild artichoke thistle” (Cynara cardunculus var. sylvestris), found in natural and disturbed ecosystems. Wild artichoke thistle is a Mediterranean native and the progenitor of two domesticated horticultural taxa, artichoke and cardoon. Different hypotheses regarding the origins of California plants have included introductions by 19th century Italian immigrants and the de-domestication (evolutionary reversion to wild-type morphology) of feral (escaped, free-living) cultivars. Using microsatellite markers, we compared the genetic constitutions of 12 artichoke thistle populations in California with possible progenitor populations: 17 Spanish and Italian wild populations and eight different artichoke and cardoon cultivars. Each California population was compared with its putative progenitors using STRUCTURE analysis. Our results suggest that California's artichoke thistle populations are polyphyletic. Surprisingly, two-thirds of California's populations closely matched populations from the Iberian Peninsula. Three populations matched domesticated artichoke. One population appears to have wild and cultivar hybrid ancestry. Alleles specific to Italian populations were found at low frequencies in some California plants, suggesting that Italian wild plants may have been in California, but have left a trivial genetic legacy. Given that the de-domesticated plants in this study appear to be as invasive as the wild taxon, we conclude with a discussion of the role that ferality and de-domestication may have in plant invasions.     

TRAINING, VALIDATION AND MAINTENANCE OF A PANEL TO EVALUATE THE TEXTURE OF DRY BEANS (PHASEOLUS VULGARIS L.)

The inclusion of dry beans in diets has clear health benefits. However, consumers in developed countries mainly choose beans for their sensory qualities, especially for their texture. This article describes the constitution, training and validation of a panel of judges to evaluate the texture of dry beans. The judges were trained in the perception of different textures, analyzed a wide range of beans and selected seed-coat roughness, seed-coat perceptibility and creaminess/mealiness of the cotyledon as the main attributes to be scored. After training, the panel was capable of discriminating between different varieties of beans and even between beans of the same variety grown at different locations. The analysis of the behavior of the panel in a standard tasting session 2 years after its formation showed that periodic inclusion of samples from the extremes of the scales for the attributes during tasting sessions was sufficient to keep the panel trained.

PRACTICAL APPLICATIONS

This article could serve as a guide for the training of sensory panels to evaluate the texture of dry beans. It describes the selection of the attributes on which the analysis is based, references for the extreme values of the attributes and how to train the panel. It also provides a practical example of the analysis of the behavior of the panel some time after training.     

COMPARISON OF TWO SIMPLE METHODS FOR THE MEASUREMENT OF DETECTION THRESHOLDS FOR BASIC, UMAMI AND METALLIC TASTES

Two simple methods were followed to determine detection thresholds for the taste of substances in aqueous solution. The methods applied were: a modification of the ascending method of limits and a method based on the use of scales. Detection thresholds were calculated for the four basic tastes (sweet, salty, acid, and bitterness), umami and metallic. Reference substances for each taste were sucrose, sodium chloride, citric acid, caffeine, monosodium glutamate and iron (II) sulfate heptahydrate and the results of the two methods were compared. We found that the threshold values calculated by method ASTM-679 was within the range of concentrations identified with the scales method.     

Highly Conserved Residues in the Helical Domain of Dengue Virus Type 1 Precursor Membrane Protein Are Involved in Assembly,Precursor Membrane (prM) Protein Cleavage,and Entry

The envelope and precursor membrane (prM) proteins of dengue virus (DENV) are present on the surface of immature virions. During maturation, prM protein is cleaved by furin protease into pr peptide and membrane (M) protein. Although previous studies mainly focusing on the pr region have identified several residues important for DENV replication, the functional role of M protein, particularly the α-helical domain (MH), which is predicted to undergo a large conformational change during maturation, remains largely unknown. In this study, we investigated the role of nine highly conserved MH domain residues in the replication cycle of DENV by site-directed mutagenesis in a DENV1 prME expression construct and found that alanine substitutions introduced to four highly conserved residues at the C terminus and one at the N terminus of the MH domain greatly affect the production of both virus-like particles and replicon particles. Eight of the nine alanine mutants affected the entry of replicon particles, which correlated with the impairment in prM cleavage. Moreover, seven mutants were found to have reduced prM-E interaction at low pH, which may inhibit the formation of smooth immature particles and exposure of prM cleavage site during maturation, thus contributing to inefficient prM cleavage. Taken together, these results are the first report showing that highly conserved MH domain residues, located at 20–38 amino acids downstream from the prM cleavage site, can modulate the prM cleavage, maturation of particles, and virus entry. The highly conserved nature of these residues suggests potential targets of antiviral strategy.