Characterisation of BaYMV and BaMMV Pathotypes in France

The reaction of thirty-four barley cultivars from European and Asiatic origin was analysed in six soils infected with barley yellow mosaic virus complex (BaYMV, BaMMV). These soils were selected from 16 sites for their differences in cultivar response. Amongst the six cultivars carrying the ym4 gene (Esterel, Express, Labéa, Majestic, Réjane, Vanoise), only cv Majestic was infected at one site with BaYMV and BaMMV. Concerning BaYMV, three cultivars were infected on all the soils and 19 on none of them. Twelve cultivars were differentially infected depending on the soil. In the case of BaMMV, four cultivars were infected on all the soils and 19 on none of them. Eleven cultivars were differentially infected depending on the soil. ELISA tests revealed the presence, in these soils, of variants of BaYMV and BaMMV that were able to overcome at least seven of the 12 known resistance genes (ym3, ym4, ym6, ym8, ym9, ym10, ym11) and the resistance of three varieties (Tosan Kawa 73, OU1 and Taihoku A) in which the genetic basis is unknown. Amplification by RT-PCR of the N-terminal region for three of BaYMV variants was performed. Nucleotide and amino acid sequences were determined and compared with the corresponding sequence of a common strain of BaYMV-G. A few nucleotide differences were detected between all the French isolates, but there were no strain specific amino acid differences.     

A classification system for impact-related defects in potato tubers

The type of tuber bruise that occurs for a given severity of impact indicates the condition of that tuber in relation to its impact sensitivity. This article describes a system for classifying such bruises. Such information is important because sensitive tubers can be re-conditioned (e.g., temperature and/or hydration can be adjusted) to reduce risk of bruising during harvesting and handling. Each class of bruise is described, illustrated, and related to tuber condition. The literature review illustrates the inadequacies of previous bruise evaluation systems in relating bruise type to tuber condition. Growers, processors, storage operators and fresh packers can use this system to make informed decisions on adjusting modifiable factors such as temperature, hydration level, and impact velocity to reduce impact-related defects during harvesting and handling of potatoes.     

Metal bioaccumulation and cellular fractionation in an epigeic earthworm (Lumbricus rubellus): The interactive influences of population exposure histories, site-specific geochemistry and mitochondrial genotype

Subcellular fractionation techniques were used to describe temporal changes (at intervals from T₀ to T₇₀ days) in the Pb, Zn and P partitioning profiles of Lumbricus rubellus populations from one calcareous (M_DH) and one acidic (M_CS) geographically isolated Pb/Zn-mine sites and one reference site (C_PF). M_DH and M_CS individuals were laboratory maintained on their native field soils; C_PF worms were exposed to both M_DH and M_CS soils. Site-specific differences in metal partitioning were found: notably, the putatively metal-adapted populations, M_DH and M_CS, preferentially partitioned higher proportions of their accumulated tissue metal burdens into insoluble CaPO₄-rich organelles compared with naive counterparts, C_PF. Thus, it is plausible that efficient metal immobilization is a phenotypic trait characterising metal tolerant ecotypes. Mitochondrial cytochrome oxidase II (COII) genotyping revealed that the populations indigenous to mine and reference soils belong to distinct genetic lineages, differentiated by ∼13%, with 7 haplotypes within the reference site lineage but fewer (3 and 4, respectively) in the lineage common to the two mine sites. Collectively, these observations raise the possibility that site-related genotype differences could influence the toxico-availability of metals and, thus, represent a potential confounding variable in field-based eco-toxicological assessments.     

Changes in wettability of heat-treated wood due to artificial weathering

Effect of artificial weathering on the wettability of three heat-treated North American wood species (jack pine, aspen, and birch) is studied from the point of view of the structural and chemical changes taking place on the wood surface. Weathering increases wettability of all three heat-treated woods by water. Changes in wettability during artificial weathering differ according to heat treatment procedure and wood species and are likely due to combination of structural and chemical changes of the surfaces. Scanning electron microscopic analysis indicates that cracks form due to degradation taking place during weathering. As a result, water has easier entry into the cell wall, which consequently increases wettability. IR spectra suggest that the OH/CH₂ ratio for heat-treated specimens is inversely proportional to the contact angle regardless of the type of wood species. The presence of cellulose-rich layer on wood surface and increasing amount of amorphous cellulose transformed from crystallized cellulose due to weathering result in increase in hydroxyl; consequently, it increases heat-treated wood wettability.     

Pericarps retained in the tree canopy and stomatal abundance are components of resistance to husk spot caused by <Emphasis Type="Italic">Pseudocercospora macadamiae</Emphasis> in macadamia

Pseudocercospora macadamiae Beilharz, Mayers and Pascoe infects macadamia fruit via stomata causing husk spot disease. Information on the variability of fruit stomatal abundance, its association with diseased fruit pericarps (sticktights) that are retained in the tree canopy, and its influence on the husk spot intensity (incidence, severity and lesion number) among macadamia genotypes is lacking. We examined a total of 230 macadamia trees comprising 19 cultivars, 56 wild germplasm accessions and 40 breeding progeny, for the prevalence of sticktights and husk spot intensity over three production seasons. We observed a strong association between the prevalence of sticktights and disease intensity indicating its usefulness as a predictor of husk spot and as a useful phenotypic trait for husk spot resistance selection in breeding programmes. Similarly, stomatal abundance varied among macadamia genotypes, and a significant linear relationship (P < 0.001; 93%) was observed between fruit stomatal abundance and husk spot for all the macadamia genotypes analysed, confirming the utility of that trait for disease resistance screening. The genotypes were grouped into disease resistance groups. Correlations between fruit stomatal abundance, disease intensity and prevalence of sticktights revealed that the numbers of sticktights, and relative stomatal abundance were the main factors influencing the intensity of husk spot among macadamia genotypes. This is the first comprehensive study of natural variation of stomatal abundance in Macadamia species that reveals genetic variation, and provides relevant relationships with disease intensity and the prevalence of sticktights. The phenotypic plant traits indentified in this study may serve as selection tools for disease resistance screening in macadamia breeding programmes.     

Geometric analysis of the proximal femur in a diverse sample of dogs

Dogs are often used as experimental models for studies of human hip replacement. A precise knowledge of femoral morphology is required to improve osteointegration of cementless prostheses by bone ingrowth or determination of the best design for total hip prostheses. To better understand the differences between breeds, we measured or calculated 24 external and internal features of the femur on standard radiographs of dogs that differed greatly in size and body type. We considered the appropriateness of the canine model for human total hip replacement studies and show that human and canine femurs differ in characteristics like anteversion, cortico-medullary index or endosteal shape. Knowledge of these differences and similarities makes it possible to design well-adapted stems for dogs.     

Application of stable carbon isotope analysis to the detection of testosterone administration to cattle

The use of anabolic substances is prohibited in food-producing animals throughout the European Union. No method is available to reliably detect the misuse of natural hormones in cattle. A method was developed to detect the abuse of testosterone in cattle fattening. Synthesized testosterone is rather depleted in the (13)C/(12)C ratio. Hence, the method is based on gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) analysis of urine. To select testosterone metabolites and endogenous reference compounds (ERC), the concentration of urinary steroids of cattle was investigated. Dehydroepiandrosterone and androst-5ene-3beta,17alpha-diol were chosen as ERCs to show endogenous (13)C/(12)C ratios. Etiocholanolone and 5alpha-androstane-3beta,17alpha-diol were chosen as the most important testosterone metabolites. Other metabolites known from literature like epitestosterone were less promising. In principle, GC/C/IRMS is a nonspecific method because finally carbon dioxide is analyzed. Therefore, a dedicated cleanup procedure for the selected steroids was developed. By means of proposed confidence intervals in the isotopic composition of ERCs and metabolites, the administration of testosterone to cattle could be detected reliably. Differences of up to 11 per thousand on the delta-scale between ERC and testosterone metabolites were found after testosterone administration, whereas endogenous differences did not exceed 2 per thousand.     

Mercury accumulation in delphinidae

The aim of this work is an attempt to synthetize the different results of our researches on dolphin's contamination by Hg and their interpretation. It is based on the results obtained following the total Hg determination in several organs of 35 specimens of Stenella coeruleoalba stranded on French Atlantic and Mediterranean coasts and 45 Stenella attenuata captured in the Eastern tropical Pacific. Considering our present knowledge on Hg ecotoxicological processes, the trophic route, via cumulative Hg transfers through the marine trophic network, can be considered as the major contamination route for the dolphins. However, considering the influence of the geographical origin of the individuals it also seems reasonable to assume that the principal contamination source of the high Hg concentrations observed in pelagic dolphins are natural metal deposits.     

Morphometry of the heart of greater rhea (Rhea americana americana,Linnaeus, 1758)

Heart diseases in birds are frequent and generate significant production disorders. Morphometry is a valuable tool to provide fundamental information about heart conditions. Few studies have addressed morphological aspects of the heart of ratite birds, such as the Greater rhea. The present study aimed to analyse rhea heart morphometry, comparing young and adult subjects, in order to provide relevant information for the diagnosis of heart disease in this species. Hearts of young (n = 10) and adult (n = 10) female rheas were used in this research. Heart length and width and sternum length were measured using a caliper. Heart length and width and sternum length in adults were approximately three times greater than in young individuals. The left ventricular wall (LVW) was thicker than the right ventricular wall (RVW) at all ages, and the RVW was thicker in adults when compared to young subjects. The basal and middle RVW regions thicken with advancing age, and the thickness of the interventricular septum (ISW) occupies an intermediate position between the LVW and RVW. In general, an increase in rhea heart thickness and size relative to age is observed. The morphometric variations between young and adult rhea hearts observed in the present study may serve as a comparative subsidy for the diagnosis of cardiac abnormalities observed in this species.