Integrating geo-referenced multiscale and multidisciplinary data for the management of biodiversity in livestock genetic resources.

In livestock genetic resource conservation, decision making about conservation priorities is based on the simultaneous analysis of several different criteria that may contribute to long-term sustainable breeding conditions, such as genetic and demographic characteristics, environmental conditions, and role of the breed in the local or regional economy. Here we address methods to integrate different data sets and highlight problems related to interdisciplinary comparisons. Data integration is based on the use of geographic coordinates and Geographic Information Systems (GIS). In addition to technical problems related to projection systems, GIS have to face the challenging issue of the non homogeneous scale of their data sets. We give examples of the successful use of GIS for data integration and examine the risk of obtaining biased results when integrating datasets that have been captured at different scales.

Heavy metal transporters in Hemiascomycete yeasts.

We have compiled all known heavy metal transporters of the yeast Saccharomyces cerevisiae and identified their orthologs in four other species spanning the entire Hemiascomycete phylum. The 213 transporters belong to 27 distinct phylogenetic families distributed within the three classes: channels, secondary porters (permeases) and transport ATPases. They are present in all cellular membranes: plasma membranes, vacuoles, mitochondria, endoplasmic reticulum, nucleus, Golgi and various cytoplasmic vesicles. The major physiological heavy metals transported are: iron, manganese, zinc, copper, arsenite and cadmium. The major subfamilies that comprise the highest number of transporters are Siderophore-Iron Transporters (SIT) and CT2 (conjugated ABC transporters). They transport heavy metals (iron or cadmium, respectively) conjugated to organic chelators such as siderophores or glutathione. Both subfamilies are considerably amplified in the yeast Yarrowia lipolytica. The pattern of expansion and restriction of the subfamilies during the evolution of the different species is highly variable. The phylogenetic trees of the major transporters subfamilies distinguish homogenous clusters of transporters suggesting that possible different physiological or mechanistic functions evolved independently. We also validated the use of the Hemiascomycetes heavy metal transporters for identification of orthologs transporters in the pathogenic Basidiomycetes Cryptococcus neoformans.

Enzyme kinetics by mid-infrared spectroscopy: beta-fructosidase study by a one-step assay.

An alternate method for enzyme study is proposed. Multidimensional statistical analysis applied on mid-infrared attenuated total reflectance spectra (Cadet et al. (1991) Appl. Spectrosc. 42, 166-172) collected during a kinetic allows a direct and fast quantification of the remaining substrate, as well as a one step enzymatic assay. Furthermore, the combination of these techniques may be used as a structural tool. The method applied to the study of beta-fructosidase is developed in this paper as an example. With appropriate calibration, the method may be extend to any enzyme.

Role of input self-sufficiency in the economic and environmental sustainability of specialised dairy farms.

Increasing input self-sufficiency is often viewed as a target to improve sustainability of dairy farms. However, few studies have specifically analysed input self-sufficiency, by including several technical inputs and without only focussing on animal feeding, in order to explore its impact on farm sustainability. To address this gap, our work has three objectives as follows: (1) identifying the structural characteristics required by specialised dairy farms located in the grassland area to be self-sufficient; (2) analysing the relationships between input self-sufficiency, environmental and economic sustainability; and (3) studying how the farms react to a decrease in milk price according to their self-sufficiency degree. Based on farm accounting databases, we categorised 335 Walloon specialised conventional dairy farms into four classes according to their level of input self-sufficiency. To this end, we used as proxy the indicator of economic autonomy - that is, the ratio between costs of inputs related to animal production, crop production and energy use and the total gross product. Classes were then compared using multiple comparison tests and canonical discriminant analysis. A total of 30 organic farms - among which 63% had a high level of economic autonomy - were considered separately and compared with the most autonomous class. We showed that a high degree of economic autonomy is associated, in conventional farms, with a high proportion of permanent grassland in the agricultural area. The most autonomous farms used less input - especially animal feeding - for a same output level, and therefore combined good environmental and economic performances. Our results also underlined that, in a situation of decrease in milk price, the least autonomous farms had more latitude to decrease their input-related costs without decreasing milk production. Their incomes per work unit were, therefore, less impacted by falling prices, but remained lower than those of more autonomous farms. In such a situation, organic farms kept stable incomes, because of a slighter decrease in organic milk price. Our results pave the way to study the role of increasing input self-sufficiency in the transition of dairy farming systems towards sustainability. Further research is required to study a wide range of systems and agro-ecological contexts, as well as to consider the evolution of farm sustainability in the long term.

Hydroxyquinolines as iron chelators.

The interest in synthetic siderophore mimics includes therapeutic applications (iron chelation therapy), the design of more effective agents to deliver Fe to plants and the development of new chemical tools for studies of iron metabolism and for a better understanding of iron assimilation processes in living systems. The 8-hydroxyquinoline bidentate chelate moiety offers an alternative to the usual hydroxamic acid, catechol and/or alpha-hydroxycarboxylic acid metal-binding groups encountered in natural siderophores. The promising results obtained by the tris hydroxyquinoline-based ligand O-TRENSOX are summarized. O-TRENSOX exhibits a high and selective affinity for Fe(III) complexation. Its efficiency in delivering Fe to plants as well as its efficiency for iron mobilization, cellular protection and antiproliferative effects have been evidenced. Other chelators of the O-TRENSOX family (mixed catechol / 8-hydroxyquinoline ligands, lipophilic ligands) are also described. Some results question whether the use of partition coefficients is pertinent to foresee the activity of iron chelators. The development of probes (fluorescent, radioactive, spin labelled) based on the O-TRENSOX backbone is in progress. 8-hydroxyquinoline iron chelators seem to have a promising future.

Life-span of Drosophila melanogaster in highly oxygenated atmospheres.

The life-span of Drosophila melanogaster males kept for their entire life in atmospheres of differing O2 concentration (21%, 30%, 40%) was measured. The life-span decreased linearly with the increase in O2 proportion. In order to test the rate of living and the threshold theories of ageing, Drosophila melanogaster males were kept for 15 days in a given atmosphere and from day 16 on in another one. The life-spans observed in these alternate conditions were very close to the values predicted by the rate of living theory and are thus not compatible with the threshold theory.

Iron mobilisation and cellular protection by a new synthetic chelator O-Trensox.

We tested a new synthetic, 8-hydroxyquinoline-based, hexadentate iron chelator, O-Trensox and compared it with desferrioxamine B (DFO). Iron mobilisation was evaluated: (i) in vitro by using ferritin and haemosiderin; DFO mobilised iron much more rapidly from ferritin at pH 7.4 than did O-Trensox, whereas at pH 4, ferritin and haemosiderin iron mobilisation was very similar with both chelators; (ii) in vitro by using cultured rat hepatocytes which had been loaded with 55Fe-ferritin; here DFO was slightly more effective after 100 hr than O-Trensox; (iii) in vivo administration i.p. to rats which had been iron-loaded with iron dextran; O-Trensox mobilised 51.5% of hepatic iron over two weeks compared to 48.8% for DFO. We also demonstrated the effect of O-Trensox in decreasing the entry of 55Fe citrate into hepatocyte cultures. The protective effect of O-Trensox against iron toxicity induced in hepatocyte cultures by ferric citrate was shown by decreased release of the enzymes lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotranferase (ALT) from the cultures and, using electron paramagnetic resonance (EPR) measurements, decreased production of lipid radicals. O-Trensox was more effective than DFO in quenching hydroxyl radicals in an acellular system.

New 8-hydroxyquinoline and catecholate iron chelators: influence of their partition coefficient on their biological activity.

Four new hexadendate chelators, three hydroxyquinoline-based, Csox, O-Trensox, Cox750, and one catecholate-based CacCam-which have comparable skeletal structures and pFe, but widely different partition coefficients, (Kpart), 0.01, 0.02, 1 and 3.2 respectively, have been tested for their iron chelating efficacy in vitro by two methods. First, by their ability to remove iron from ferritin in solution or second, to remove iron from iron-loaded hepatocytes in vitro. Our objective was to ascertain the importance of Kpart and pFe, on the biological efficiency of the molecule. Previous studies proposed that an ideal value of Kpart of 1 should give maximum biological activity. Mobilization of iron by Csox and CacCAM from ferritin was similar and furthermore more efficient than desferrioxamine B. In the iron-loaded hepatocyte cultures, the three hydroxyquinoline chelators, although showing diversity in terms of lipophilicity, appeared to be very similar in their capacity to chelate iron. CacCAM, the unique catecholate, was the most efficient of the molecules tested, as well as being the least toxic in the cellular model despite having the lowest value of pFe. In conclusion, the use of the partition coefficient and pFe, as tools for predicting biological activity of iron chelators should be not generalized. Further studies are required in order to understand the influence of the structure on the biological activity of the molecule.

Quantitative trait loci for resistance against Yellow rust in two wheat-derived recombinant inbred line populations.

Yellow rust, which is a major disease in areas where cool temperatures prevail, can strongly influence grain yield. To control this disease, breeders have extensively used major specific resistance genes. Unfortunately this kind of resistance is rapidly lost due to pathogen adaptation. More-durable resistance against yellow rust can be achieved using quantitative resistance derived from cultivars with well-established durable resistance. The winter wheat Camp Remy has maintained a high level of resistance for over 20 years. In order to map quantitative trait loci (QTLs) for durable yellow rust resistance, we analysed a set of 98 F(8) recombinant inbred (RI) lines derived from the cross Camp RemyxMichigan Amber. We also mapped QTLs for adult resistance to yellow rust using the International Triticae Mapping Initiative RI population (114 lines derived from the cross Opata85xsynthetic hexaploid). Two and five QTLs, respectively, were identified from these two populations. This work has highlighted the importance of the centromeric region of chromosome 2B and the telomeric regions of chromosomes 2AL and 7DS in durable yellow rust resistance. The same chromosomal regions are also implicated in resistance to other pathogens.

Inhibition of lipid peroxidation by a new family of iron chelators. Comparison with desferrioxamine.

Catechol derived siderophores are the most powerful currently known iron chelators. We have intended tripodal ligands built with o,o' dihydroxy biaryl subunits (A, B, and C). We described antioxidant properties of this new family of iron chelators. Superoxide-dependent hydroxyl radical system was used. Peroxidation of different lipid-containing systems (liposomes, erythrocyte membrane ghosts, tissue homogenates) were also investigated. The antioxidant properties of these new chelators have been related to that of desferrioxamine as a reference compound. In general manner, the results depended mainly on the model used in the assay. However, C presents an antioxidant effect close to that of desferrioxamine.

Evaluation of antioxidant properties of major dietary polyphenols and their protective effect on 3T3-L1 preadipocytes and red blood cells exposed to oxidative stress.

Obesity has been associated with a marked risk of metabolic diseases and requires therapeutic strategies. Changes in redox status with increased oxidative stress in adipose tissue have been linked with obesity-related disorders. Thus, the biological effect of antioxidants such as polyphenols is of high interest. We aimed to measure antioxidant capacities of 28 polyphenols representative of main dietary phenolic acids, flavonoids, stilbenes and curcuminoids. Then, 14 molecules were selected for the evaluation of their effect on 3T3-L1 preadipocytes and human red blood cells exposed to oxidative stress. Analysis of reducing and free radical-scavenging capacities of compounds revealed antioxidant properties related to their structure, with higher activities for flavonoids such as quercetin and epicatechin. Their effects on preadipocytes' viability also depended on their structure, dose and time of exposure. Interestingly, most of the compounds exhibited a protective effect on preadipocytes exposed to oxidative stress, by reversing H2O2-induced anti-proliferative action and reactive oxygen species production. Polyphenols also exerted an anti-inflammatory effect on preadipocytes exposed to H2O2 by reducing IL-6 secretion. Importantly, such antioxidant and anti-inflammatory effects were observed in co-exposition (polyphenol and prooxidant during 24 h) or pretreatment (polyphenol during 24 h, then prooxidant for 24 h) conditions. Moreover, compounds protected erythrocytes from AAPH radical-induced lysis. Finally, these results led to demonstrate that antioxidant and anti-inflammatory properties of polyphenols may depend on structure, dose, time of exposure and cell conditioning with oxidative stress. Such findings should be considered for a better understanding of polyphenols' benefits in strategies aiming to prevent obesity-related diseases.

Multigan®: first experimental results.

A new design of a multicharged ion source based on the MONO1000 ECRIS has been presented at the last ECR ion source (ECRIS) Workshop 2010. [L. Maunoury et al., in Proceedings of the XIXth International Workshop on ECR Ion Sources, Grenoble, France, 23-26 August 2010] This source has not only two opening at both ends but also a large space in the middle of the source enabling a direct contact with the ECR plasma. The source has been assembled mechanically and put on a test bench at the Pantechnik company. The primary tests have shown that the plasma ignition occurred at low pressure (10(-6) mbar) and low RF power (10 W). The first experimental results ( = 1.30 for Ar and 1.85 for Xe) demonstrated the potential of this ion source in production of multicharged ion beams.

Selection for increased longevity in Drosophila melanogaster: a new interpretation.

The study of the genetic determination of longevity in Drosophila melanogaster has made use of the technique of late-age reproduction. At low larval density, that indirect selection showed no effect. At high larval density, however, increased mean life-span in lines reproduced at late age was observed. When these last data are examined as a function of the number of days after the beginning of the experiment, instead of as a function of generations, the difference in life-span between early and late lines at high larval density disappears. The erratic evolutions of mean longevities in all the experiments here described may be attributed to unexplained variations in life-span previously observed in a 4-year experiment. Considering the time lag between the measurement of a given generation in early and late lines, the experiments of reproduction at late age cannot demonstrate the genetic determinism of longevity.

A mild stress due to hypergravity exposure at young age increases longevity in Drosophila melanogaster males.

Drosophila melanogaster flies were exposed to hypergravity starting at two days of age, the range of gravity levels used being 2.58-7.38 g. No longevity change was observed for exposures of less than 14 days. The longevity of males increased if they were submitted to hypergravity for durations ranging from 14 to 24 days. This increase in longevity was never observed in females. The positive effect of exposure to hypergravity has been replicated in two laboratories using two wild-type strains and different rearing conditions. A short hypergravity exposure seems to be a mild stress, yielding positive effects on longevity. This is in accordance with two previous studies showing a slight longevity increase after heat shock in the nematode Caenorhabditis elegans and in Drosophila melanogaster.

Realized heritability of longevity in Drosophila melanogaster.

From the data of an experiment of selection for increased longevity, a realized heritability of longevity was calculated. The low value of this heritability (3.4%) was very close to values observed in other experiments concerning Drosophila melanogaster wild strains. The error variance of the heritability estimator was calculated through the use of orthogonal contrasts. In this way, it was possible to calculate the confidence interval of the realized heritability. The amplitude of this interval was wide although the size of the sample was large. This shows the difficulty of estimating with precision the heritability of longevity from data obtained in selection experiments.

Selection for increased longevity in Drosophila melanogaster: reflections on new data.

In recent papers, new data were presented on the late-age reproduction experiment initiated by Luckinbill and Clare in 1981: when early- and late-reproduced lines were compared simultaneously 10 years after the end of the original experiment, differences in the mean life span are observed between the lines. Yet the conditions in which these measurements were done are highly questionable. More fundamentally, using these data, the analysis of the selection process is impossible and conclusions about the determinism of life span are debatable.

On the use of linear regression and maximum likelihood for QTL mapping in half-sib designs.

Methods of identification of quantitative trait loci (QTL) using a half-sib design are generally based on least-squares or maximum likelihood approaches. These methods differ in the genetical model considered and in the information used. Despite these differences, the power of the two methods in a daughter design in very similar. Using an analogy with a one-way analysis of variance, we propose an equation connecting the two test-statistics (F ratio for regression and likelihood ratio test in the case of the maximum likelihood). The robustness of this relationship is tested by simulation for different single QTL models. In general, the correspondence between the two statistics is good under both the null hypothesis and the alternative hypothesis of a single QTL segregating. Practical implications are discussed with particular emphasis on the theoretical distribution of the likelihood ratio test.

[Enzymatic kinetics and mid-infrared spectroscopy combined with multidimensional data analysis]. / Cinétique enzymatique et spectroscopie moyen infrarouge combinée avec l'analyse multidimensionnelle de données.

An alternate method for enzyme study is proposed. This technique allows enzymatic reactions by a one step assay, and visualisation of variations in FTIR spectral data of substrate during the reaction. Hydrolysis of sucrose by beta-fructosidase is carried out as an example.