Effects of management regimes and extreme climatic events on plant population viability in Eryngium alpinum

Extreme climatic events like the 2003 summer heatwave and inappropriate land management can threaten the existence of rare plants. We studied the response of Eryngium alpinum, a vulnerable species, to this extreme climatic event and different agricultural practices. A demographic study was conducted in seven field sites between 2001 and 2010. Stage-specific vital rates were used to parameterize matrix population models and perform stochastic projections to calculate population growth rates and estimate extinction probabilities. Among management regimes, spring grazing and land abandonment decreased vital rates and population growth, while autumn grazing and late mowing had positive effects on population viability. The 2003 heatwave reduced fecundity rates and survival rates. Only spring grazed sites presented considerable extinction risk. Stochastic projections showed that an increased frequency of 2003-like events may exacerbate extinction risk, but extinction probability depends mainly on land management regimes. To better conserve E. alpinum populations, we recommend conversion of presently spring grazed and abandoned sites to late mowing or autumn grazing.     

Modifications of Interfacial Proteins in Oil-in-Water Emulsions Prior to and During Lipid Oxidation

Lipid oxidation is a major cause for the degradation of biological systems and foods, but the intricate relationship between lipid oxidation and protein modifications in these complex multiphase systems remains unclear. The objective of this work was to have a spatial and temporal insight of the modifications undergone by the interfacial or the unadsorbed proteins in oil-in-water emulsions during lipid oxidation. Tryptophan fluorescence and oxygen uptake were monitored simultaneously during incubation in different conditions of protein-stabilized oil-in-water emulsions. Kinetic parameters demonstrated that protein modifications, highlighted by decrease of protein fluorescence, occurred as an early event in the sequence of the reactions. They concerned more specifically the proteins adsorbed at the oil/water interface. The reactions led in a latter stage to protein aggregation, carbonylation, and loss of protein solubility.     

Prediction of soil organic and inorganic carbon contents at a national scale (France) using mid‐infrared reflectance spectroscopy (MIRS)

This work aimed to evaluate the potential of mid‐infrared reflectance spectroscopy (MIRS) to predict soil organic and inorganic carbon contents with a 2086‐sample set representative of French topsoils (0–30 cm). Ground air‐dried samples collected regularly using a 16 × 16‐km grid were analysed for total (dry combustion) and inorganic (calcimeter) carbon; organic carbon was calculated by difference. Calibrations of MIR spectra with partial least square regressions were developed with 10–80% of the set and five random selections of samples. Comparisons between samples with contrasting organic or inorganic carbon content and regression coefficients of calibration equations both showed that organic carbon was firstly associated with a wide spectral region around 2500–3500 cm^?1 (which was a reflection of its complex nature), and inorganic carbon with narrow spectral bands, especially around 2520 cm^?1. Optimal calibrations for both organic and inorganic carbon were achieved by using 20% of the total set: predictions were not improved much by including more of the set and were less stable, probably because of atypical samples. At the 20% rate, organic carbon predictions over the validation set (80% of the total) yielded mean R², standard error of prediction (SEP) and RPD (ratio of standard deviation to SEP) of 0.89, 6.7 g kg^?1 and 3.0, respectively; inorganic carbon predictions yielded 0.97, 2.8 g kg^?1 and 5.6, respectively. This seemed appropriate for large‐scale soil inventories and mapping studies but not for accurate carbon monitoring, possibly because carbonate soils were included. More work is needed on organic carbon calibrations for large‐scale soil libraries.     

Free fatty acids in Lake Aydat catchment soils (French Massif Central): sources,distributions and potential use as sediment biomarkers

Purpose  

Eighteen soils were sampled in the Lake Aydat catchment in order to analyse free fatty acid (FA) content; FAs are considered to be among the most amenable biomarkers to mobilisation by runoff waters. The majority of the study area has soil cover consisting of grasslands or forest since the 2nd World War, although some covers having changed more recently.     

Selectivity of the root absorption of nutrient ions in grain sorghum

Root absorption selectivity, which refers to the fact that the mineral elements are not found in the same proportions in the plant as in the growth medium, was characterized using plots where the proportions between the elements were considered. Grain sorghum was grown hydroponically in nutrient solutions where the cationic macroelements were increasingly replaced with sodium and the anionic macronutrients with chloride. The data obtained from the analyses of the nutrient solutions and of the whole plants show that root selectivity promotes the absorption of K⁺ and NO₃ ^‐ ‐N and impedes that of Ca⁺⁺ whereas there is nearly no selectivity towards the other nutrients (Mg, P, S).The high negative selectivity towards unessential elements (Na and Cl) is reflected by their very low proportions within the plant.

The comparison between the various plant organs shows that the proportions of the essential elements are nearly identical in the roots, the sheaths, the younger leaves and in the adult leaves (only for the anions). The differences observed for the older leaves are to be assigned to their senescence status which conditions the possibilities of translocation of the elements within the plant.     

Population Growth of Myzus persicae on Potato Plants Infected with Different Strains and Variants of Potato virus Y

Potato virus Y (PVY) is one of the most economically important viruses affecting the potato crop. Several strains of the virus, including PVY^O, PVY^N, recombinant isolates; PVY^N:O (PVY ^N-Wi) and PVY^NTN and several variants of PVY^O have been reported from North American potato-production areas. The green peach aphid, Myzus persicae Sulzer, is a colonizer of potatoes and is considered the most important vector of PVY. The objective of this study was to measure the population growth of M. persicae on potato plants infected with different strains and genetic variants of PVY. The initial population of ten winged adults of M. persicae was allowed to develop on a potted plant for 12 days. Results clearly indicated that infections by different strains and genetic variants of PVY did not influence the population growth of M. persicae on potato plants during this period.     

Accreditation for freedom from ovine brucellosis

The results of operating a voluntary ovine brucellosis accreditation programme in 14 stud and 9 commercial flocks in the Manawatu district is reported. From a total of 1992 CF test results there were 47 positive and 14 suspicious reactions; a total of 61 reactions (3.06%). Fifty six of these occurred in rams vaccinated during the previous 12 months, and only one further ram with epididymitis had a suspicious, and then a positive, CF test and is assumed to have had brucellosis (0.05%). One of the remaining three suspicious reactions was confirmed as a false suspicious, and the other two remain unclassified as either true or false. It was concluded the CF test is both highly sensitive and specific, and that the official acceptance of accreditation schemes is an urgent priority for the sheep industry.     

Atherosclerosis: Comparative Pathogenesis,Lipoprotein Metabolism,and Avian and Exotic Companion Mammal Models

Atherosclerosis is a chronic inflammatory disease of the arterial wall where the accumulation of foam cells, lipids, calcium, and cellular debris leads to large fibrofatty atheromatous plaques narrowing the arterial lumen. As the principal cause of human deaths in the world, the pathogenesis of atherosclerosis has been extensively studied, as well as lipid and lipoprotein metabolism, across species. Important aspects of the disease were first investigated experimentally in a wide array of animal models, including laboratory avian and mammalian species also kept as companion pets. Although the disease is primarily a significant clinical entity in avian patients, the wealth of information obtained from companion exotic mammals is of interest to understand the complex comparative pathogenesis of atherosclerotic lesions. This review presents the current concepts of atherogenesis and lipoprotein metabolism followed by a brief overview of species peculiarities as it relates to the experimental reproduction of the disease. This overview should provide interesting insight on atherosclerosis, which spontaneously or experimentally affects many zoological companion species commonly seen by veterinarians.     

A Case of Atypical Psoroptic Mange in a Domestic Rabbit

A female checkered giant cross rabbit (Oryctolagus cuniculus) was presented with skin lesions on the perineal region. The cutaneous lesions extended 2 cm from the vulva and perineal glands. They were moist and erythematous, with abundant greasy yellowish scabs. Skin scrapings from the lesions were mounted in Amman’s chloral-lactophenol on microscope slides and examined at ×10 and ×40 magnification. Numerous mites were observed and identified as Psoroptes cuniculi, a common causal agent of otitis externa in rabbits. The rabbit was treated successfully with ivermectin. This case of psoroptic mange is atypical owing to the perineal location, apparent absence of auricular lesions, and the lack of contagion despite close contact with several other rabbits.