Transformation of Eutypa dieback and esca disease pathogen toxins by antagonistic fungal strains reveals a second detoxification pathway not present in Vitis vinifera

Eutypine, 4-hydroxybenzaldehyde, and 3-phenyllactic acid are some of the phytotoxins produced by the pathogens causing Eutypa dieback and esca disease, two trunk diseases of grapevine (Vitis vinifera). Known biocontrol agents such as Fusarium lateritium and Trichoderma sp. were screened for their ability to consume these toxins. Transformation time courses were performed, and an high-performance liquid chromatography-based method was developed to analyze toxin metabolism and to identify and quantify the converted products. The results show that the aldehyde function of eutypine was reduced to eutypinol, as by V. vinifera cv. Merlot, the cultivar tolerant to Eutypa dieback. We revealed a supplementary detoxification pathway, not known in Merlot, where the aldehyde function was oxidized to eutypinic acid. Moreover, some strains tested could further metabolize the transformation products. Every strain tested could transform 4-hydroxybenzaldehyde to the corresponding alcohol and acid, and these intermediates disappeared totally at the end of the time courses. When biological assays on cells of V. vinifera cv. Chasselas were carried out, the transformation products exhibited a lower toxicity than the toxins. The possibility of selecting new biocontrol agents against trunk diseases of grapevine based on microbial detoxification is discussed.     

Arbuscular Mycorrhizal Fungal Infectivity in Two Soils as Affected by Atmospheric Phenanthrene Pollution

Arbuscular mycorrhizal fungi (AMF) hold a crucial role in ecosystems because they are involved in nutrient cycling between soil and plants. This work aimed at evaluating the impacts that atmospheric pollution by polycyclic aromatic hydrocarbons may have on infectivity of indigenous AMF in soils. Two agricultural soils (Maconcourt, La Bouzule) were exposed for 2?weeks to ambient air (control, C) or to atmospheric phenanthrene (PHE) deposition (180???g?m^?3 air). After exposure, soils were divided into a top (0?C1?cm) and a bottom (1?C15?cm) layer fraction. AMF infectivities of soils were determined after 2?weeks of atmospheric exposition using leek (Allium porum) as bioassay plant. Atmospheric PHE was mainly recovered in the top layer of soil (500?C1,350???g?kg^?1) of both soils and did not readily diffuse into the depth. Atmospheric contamination led to decreases in AMF infectivities of the top layer in both soils and affected the growth of leeks. Our results not only report evidence that infectivity of indigenous AMF is sensitive to PHE in soils but also emphasize that AMF are primary affected by the soil layer regardless to the pollution level.     

Transport of phosphorus in leaf veins of Vicia faba L.

The plant nutrient phosphorus (P) is spread throughout the plant within the transpiration stream after uptake in the form of phosphate via the roots. Short‐term distribution is therefore strongly dependent on transpiration rather than on sinks, so that P mainly enters adult leaves. The objective of this work was to investigate the transport of phosphate in leaf veins and its distribution within the leaf. Experiments were performed with broad bean (Vicia faba L. var. Scirocco) using radioactively labeled phosphate. In a relatively new approach, the tracer was monitored by a sensitive imaging plate using Fujifilm's Bioimaging Analyzer System. Radioactive label could be monitored in fresh leaves (without fixing) using exposure times of only 5–20 min. For this reason, the method offered the possibility to obtain several subsequent autoradiographic images of the same sample after different feeding times. Phosphate tracer quickly reached small veins, which were then more intensely labeled than the tissue between them. Within the first 15 min, intercostal fields were only slightly stained. After application of phosphate tracer onto the leaf blade, export from the leaf was pronounced and started within 30 min. Phosphorus is effectively redistributed from adult leaves to sinks such as the terminal bud or growing root tips. Using the imaging method, an impression of the high velocity and effectiveness of this process was obtained. The results furthermore imply that leaf veins may be one of the most important locations where exchange between xylem and phloem transport takes place, although exchange between xylem and phloem was also observed in the shoot axis and in the petioles.     

Sustainability and multifunctionality in French farms: Analysis of the implementation of Territorial Farming Contracts

Sustainable agriculture and ways to achieve it are important issues for agricultural policy. However, the concept of sustainability has yet to be made operational in many agricultural situations, and only a few studies so far have addressed the implementation process of sustainable agriculture. This paper provides an assessment of the Territorial Farming Contracts (TFC) – the French model for implementing sustainable agriculture – and aims to give some insights into the ways to facilitate the development of sustainable farming. Using a systems approach, the founding concept of the TFC model, an analysis has been made of the TFCs signed in the Midi-Pyrenees Region in south-western France. The results show that the first aspect of sustainability apparent in farmers’ projects referred to economic objectives. The environmental and social aspects were not foremost in the farming changes undertaken. In addition, the territorial dimension of the TFC was under-addressed. The majority of TFCs reveal a moderate or even low convergence with territorial priorities. These results are explained partly by the dominance of professional farming organizations in the implementation of TFC, and they imply that the organizational social dimensions of sustainability must not be neglected. Mohamed Gafsi is an assistant professor of farm management at the National School of Agronomic Training. He received his PhD in management science at the University of Bourgogne. His research interests include farm management and protection of natural resources, corporate environmental management, sustainable agriculture, and African family farms. Geneviève Nguyen is assistant professor in rural economics at the National Polytechnique Institute – National Superior School of Agronomy, in Toulouse. Her research interests include the dynamics of agrarian institutions in uncertain economies, the supply and organization of services in remote rural areas. Her research has been carried out in Europe, Africa, and Asia. She received her MA in Economics and her PhD in Agricultural Economics from the Ohio State University. Bruno Legagneux is assistant professor of farm management at the National Polytechnique Institute – National Superior School of Agronomy, in Toulouse. His research interests include farm management and the entry of young farmers into farming. Patrice Robin is an engineer agronomist. He received his diploma from the National Superior School of Agronomy, in Montpellier. He is currently a doctoral candidate at the University of Toulouse. His research interests include agriculture and rural development, environmental issues, and food quality.     

Alteration of virulence factors and rearrangement of pAsa5 plasmid caused by the growth of Aeromonas salmonicida in stressful conditions

Aeromonas salmonicida, a fish pathogen, is the causative agent of furunculosis. It was already shown that growing this bacterium in stressful conditions such as temperature above 22°C might lead to virulence attenuation. Unfortunately, many veterinary microbiology services and reference centers still routinely cultivate A. salmonicida at 25°C. Here we tested the presence of virulence factors by growth on specific medium as well as the integrity of the pAsa5 plasmid, which bears an important virulence factor, the type III secretion system (TTSS), by PCR analysis in twenty strains, most of which were grown at 25°C in their laboratory of origin. The analysis revealed that strains, which encountered the more stressful growth conditions displayed the most frequent absence of A-layer protein and secreted proteolytic activity. Moreover, many strains had lost parts of the pAsa5 plasmid in which the TTSS region was almost always affected. To confirm the effect of stressful growth conditions on the plasmid, three strains with an intact pAsa5 were cultured at 25°C for two weeks. A low but significant fraction of the tested colonies displayed pAsa5 rearrangements. The rearrangement always affected the TTSS region and led to a loss of virulence in the Dictyostelium discoideum co-culture assay. These results demonstrate that the instability of pAsa5 did not lead to its complete loss as previously proposed but to a more complex rearrangement phenomenon and emphasizes the necessity to grow A. salmonicida in appropriate conditions to preserve the complete virulence of the bacterium.     

Hematologic evaluation of normal and anemic lambs with the Technicon H*1 using EDTA or heparin as anticoagulants

Abstract: A study was performed to evaluate blood from young lambs using the Technicon H*1 hematology analyzer, with emphasis on RBC parameters, comparison of tripotassium EDTA and heparin, and the effects of storage on heparinized blood. Blood samples from lambs 2 days to 18 weeks of age were analyzed within 6 hours, revealing a high precision, except for WBC counts in heparinized blood. The HCT values estimated by the H*1 correlated well (r²= .90) with those obtained by the microhematocrit method. Mean hematologic values obtained for heparinized blood differed by up to 4% from values obtained for blood collected into EDTA. WBC counts decreased 8.4% in heparinized blood stored at 4°C for 1 day, but differences observed in RBC counts were ≤ 2%. Problems occurred when analyzing blood from young lambs with low hemoglobin values because the H*1 incorrectly counted microcytes with volumes of < 10 fL as platelets. When the necessary corrections were performed, the H*1 was useful for analyzing RBC parameters in lamb blood collected both into EDTA and into heparin.     

Ultrasonographic fetal well-being assessment, neonatal and postpartum findings of cloned pregnancies in cattle: A preliminary study on 10 fetuses and calves

Cloned pregnancies in cattle are considered to be at risk due to a variety of fetal or adnexal abnormalities. Data is lacking concerning the possibility of transabdominal ultrasonography in the assessment of these high risk pregnancies. Transabdominal ultrasonography has rarely been reported in the assessment of bovine cloned pregnancies. Ten Holstein heifers carrying 8-month-old cloned fetuses were assessed by transabdominal ultrasonographic examination during the 3rd trimester of pregnancy. Fetal heart rates (FHR), movements, adnexal appearance, and placentome size were recorded. The outcome of the pregnancies was also noted and potential indicators of fetal demise recorded. Survival rate 1 week after birth was 30%. Mean FHR was 113 beats per minute (range: 92 to 128 bpm) during the fetal ultrasonography. No correlation between FHR and fetal activity was found. Fetal hyperactivity and imaging of hyperechoic particles in both allantoic and amniotic fluids were possible signs of fetal distress. Despite the size of the fetus and the deep bovine abdomen, fetal transabdominal ultrasonography can be performed in cattle. This preliminary study points to the necessity of further larger studies for defining normal and abnormal findings in bovine late pregnancy.     

Exclusion of the swine leukocyte antigens as candidate region and reduction of the position interval for the Sus scrofa chromosome 7 QTL affecting growth and fatness

Pig chromosome 7 (SSC 7) has been shown to be rich in QTL affecting performance and quality traits. Most studies mapped the QTL close to the swine leukocyte antigens (SLA), which has a large effect on adaptability and natural selection. Previous comparative mapping studies suggested that the 15-cM region limited by markers LRA1 (mapped at 55 cM) and S0102 (mapped at 70 cM) contains hundreds of genes. To decrease the number of candidate genes, we improved the mapping resolution with a genetic chromosome dissection through a backcross recombinant progeny test program between Meishan (MS) and European (EU; i.e., Large White or Landrace) breeds. Three first-generation backcross--(EU x MS) x EU--and two second-generation backcross--([EU x MS] x EU) x EU--sires carrying a recombination in the QTL mapping interval were progeny-tested (i.e., measured for a total of 44 growth, fatness, carcass and meat quality traits). Progeny family size varied from 29 to 119 pigs. Animals were genotyped for markers covering the region of interest. Progeny-test results allowed the QTL interval to be decreased from 15 to 20 cM down to 10 cM, and even less than 6 cM if we assumed that the EU pigs used in this study share only one QTL allele. Except for a putative QTL affecting some carcass composition traits, the SLA is excluded as a candidate region, suggesting that it might be possible to apply a marker-assisted selection strategy for this QTL, while controlling SLA allele diversity. The strong QTL effects remaining in animals with only 12.5% (issued from first-generation backcross boars) and 6.25% (issued from second-generation back-cross boars) Meishan genetic background shows that epistatic interactions are likely to be limited. Finally, the QTL does not have strong effects on meat quality traits.     

Impact of dietary tryptophan and behavioral type on behavior, plasma cortisol, and brain metabolites of young pigs.

The behavioral reactivity in an "open-field" test and plasma cortisol levels were studied in 72 pigs from 12 litters fed for 3 wk one of three diets with different levels of tryptophan: deficient (.14%), adequate (.23%), or excess (.32%). "Open-field" tests were performed three times: 5 d (day W + 5), 23 d (day W + 23) and 45 d (day W + 45) after weaning. The exploration time and the number of grunts provided an adequate measure of the individual emotional reactivity at day W + 5. Significant correlations were obtained between exploration time and the number of grunts at each time (r = -.83 at day W + 5; r = -.46 at day W + 23; r = -.71 at day W + 45). The distinction between animals remained (P less than .05) in terms of exploration time at both 23 and 45 d after weaning. At day W + 23, exploration time was lower in the group fed the adequate diet than in the two other groups. This effect was maintained subsequently after feeding all pigs the same adequate diet (day W + 45). In 36 pigs slaughtered at day W + 23, brain TRP concentration was higher with the excess dietary TRP than with deficient or adequate levels. Conversely, other plasma amino acids (particularly threonine) accumulated only in the brains of pigs fed the deficient diet. Plasma cortisol level assayed at weaning (W) and 2 wk later increased with age and was higher in 16-h fasted (day W + 15) than in 3-h fasted (day W + 17) pigs. Correlations were observed within litters in the fasting state, between the cortisol level and behavioral traits measured at day W + 23 (r = .70 for number of grunts, r = -.60 for exploration time). Dietary TRP did not affect the plasma cortisol level irrespective of the nutritional state after weaning. However, an interaction was noted between plasma cortisol and TRP status (P less than .05). Although dietary TRP induced large variations in brain amino acids and 5-hydroxyindole concentrations, changes in behavioral and cortisol responses were relatively minor.