Genetic variability following selection for scrapie resistance in six autochthonous sheep breeds in the province of Bolzano (northern Italy)

Scrapie is an ovine transmissible spongiform encephalopathy, and its susceptibility is associated with polymorphisms in the prion protein gene (PRNP). Genetic selection is currently the most effective mean for eradication of the susceptible VRQ allele in favour of resistant ARR allele. Maintenance of genetic diversity should be one of the major objectives in breeding programmes, especially in endangered breeds, and genetic information are an excellent alternative to pedigree data where these information are missing. The aim of our study was to determine changes of genetic variability in six native sheep breeds from autonomous province of Bolzano, northern Italy, following simulation of scrapie selection scenarios. A total of 684 rams were investigated for PRNP polymorphisms and for 10 microsatellite loci to estimate genetic variability. Across all loci, a total of 163 alleles were detected with a mean of 10.4 alleles per locus. Average observed (Ho) and unbiased expected (uHe) heterozygosity overall loci were 0.74 and 0.78, respectively, showing a statistically significant deviation from Hardy–Weinberg equilibrium (HWE) in all breeds. This heterozygosity deficit was confirmed by a positive fixation index (Fis), determining a moderate inbreeding in each breed. Simulating a soft selection, where only rams having at least a VRQ allele should be excluded from reproduction, Ho, uHe and Fis values remained almost unchanged, indicating that genetic variability should not be affected by the removal of these individuals. With a mild selection scenario, considering only rams with at least one ARR allele, we observed a decrease in the mean alleles per breed (8.9) and the maintenance of heterozygosity deficiency, except for two breeds, where it was any longer significant. These results showed that selection strategies allowing use of heterozygous as well homozygous ARR rams might be the right compromise to improve resistance to scrapie and to do not dramatically affect genetic variability of these breeds.     

Mercury in soils and crops from fields receiving high cumulative sewage sludge applications: Validation of U. S. EPA's risk assessment for human ingestion

The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) has owned and operated a 6320 ha Dedicated Beneficial Sludge Utilization Site in Fulton County, Illinois since 1971. The site consists of calcareous strip mine spoil intermingled with placed land. Sewage sludge from Chicago is barged to the site, located approximately 185 miles southwest of the city, and utilized to reclaim the strip mined soils and to fertilize the corn and wheat crops grown on them. Fields have received as much as 1317 dry Mg ha^?1 of sewage sludge since 1971. Sludge Hg concentrations have ranged from 1.1 to 8.5 mg Hg kg^?1 with mean concentration of 3.31 mg Hg kg^?1, and maximum cumulative Hg loading rates are approximately 4 kg ha^?1. Sludge applications have significantly increased extractable soil Hg concentrations, and regression analysis indicates that from 80 to 100% of the Hg applied to soils in sewage sludge since 1971 still resides in the top 15 cm of soil. Since 1985 the MWRDGC has been monitoring Hg concentration in corn leaf and grain, wheat grain and soils at the Fulton County site. Monitoring data indicate that 98.8% of the corn grain samples, 93.0% of the wheat samples and 50.7% of the corn leaf samples collected from 1985 through 1992 had Hg concentrations below detectable limits (<25μg kg^?1). Cumulative Hg loading rates are utilized along with crop tissue concentrations to compute crop uptake response slopes (UC) for Hg into plant tissues at the Fulton County site. The UC for corn and wheat grain was zero and for corn leaf was ?0.0014 (mg Hg/kg tissue)/(kg Hg/ha soil), which indicate that sewage sludge additions did not increase plant tissue Hg concentrations at the Fulton County site. The negative UC obtained for corn leaf may actually indicate that sewage sludge applications decreased Hg uptake from mined soils possibly due to organic carbon and sulfides in the anaerobically digested sludge binding native Hg. The United States Environmental Protection Agency (U. S. EPA) has recently promulgated their 40 CFR Part 503 regulation for sewage sludge use and disposal. The rule sets risk based limits on ten metals, including Hg, in sludges that are land applied. Exposure pathways involving plant uptake of Hg are briefly discussed and it is shown that the UC used in U. S. EPA's risk assessment models for these pathways overpredict uptake of Hg by crops when compared with the UC derived from the MWRDGC's monitoring data at Fulton County.     

Molecular basis of the interaction between proteins of plant origin and proanthocyanidins in a model wine system

Plant proteins are being used as a replacement for animal proteins in wine fining. The surface hydrophobicity of plant proteins in four commercial preparations differing for their origin and processing was assessed by using a fluorescent hydrophobic probe in wine-like media. Displacement of the probe by addition of wine phenolics was measured as a way to compare and predict to some extent the efficiency of these proteins in wine fining. It was found that the binding of polyphenols was much more specific than that of the hydrophobic probe. Further analysis of the polyphenol pattern in protein-treated wine-like solutions pointed out two relevant facts: (1) proteins may interfere with the chemistry of the interactions between polyphenols and other wine components; (2) individual protein preparation having different surface hydrophobicities also have different specificities in binding different polymeric forms of the polyphenols and in their substitution products. These findings are related to the possible carry-over of transition metals and may be worth exploring for custom tailoring the fining process. Whether the practical application of the latter finding will call for production and/or screening of plant-derived proteins with features appropriate to this task remains to be investigated. However, the approaches presented in this study may be used for large-scale screening of protein suitability for fining application under laboratory conditions, providing guidelines for their use in actual winemaking applications.     

Pathologic findings of highly pathogenic avian influenza virus A/Duck/Vietnam/12/05 (H5N1) in experimentally infected pekin ducks, based on immunohistochemistry and in situ hybridization

The ongoing H5N1 Asian epidemic is currently affecting a number of avian species including ducks. These birds are an important part of the poultry industry in the affected countries, and it is likely that they are acting as a reservoir of infection. Ten Pekin ducks were challenged with 100 microl containing 10(7) 50% egg infective dose of the highly pathogenic avian influenza virus (HPAIV) A/Duck/Vietnam/12/05 (H5N1), administered by an intra-nasal and oral route. Clinical symptoms were recorded twice a day up to 14 days postinfection (dpi). Clinical signs were first noted at 2 dpi, with conjunctivitis and slight depression, and progressed over a period of 1-3 days to severe neurologic signs consisting of torticollis, incoordination, tremors, and seizures. Survival times varied from 3 to 7 dpi. On postmortem examination, hemorrhages were observed in the duodenum, ceca, proventriculus, ventriculus, trachea, pancreas, and brain. Histologic lesions, as well as immunohistochemistry positivity, were recorded in the pancreas and brain. In situ hybridization revealed viral antigen associated with acinar pancreatic cells, bronchial epithelial cells, and with cells of the central nervous system as well as neurons of the submucosal plexus of the duodenum. Our experimental findings agree with those previously observed in ducks naturally infected with HPAIV H5N1 viruses, confirming the acquired viral neurotropism and pancreatotropism, as previously noted in other avian species, as well as in humans.     

2,3,7,8-Tetrachlorodibenzo-p-dioxin influences bovine herpesvirus 1 replication through upregulation of SIRT3 and cytoskeletal reorganization

Infection of kidney cells (MDBK) with Bovine Herpesvirus 1 (BoHV-1) is affected by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which accelerates BoHV-1-induced apoptosis and increases virus replication. Herein, to elucidate the mechanism through TCDD modifies BoHV-1 infection, we analyzed the modulation of a members of Sirtuin proteins family in MDBK cells. We found that mitochondrial SIRT3 was upregulated during infection. This change was accompanied by cytoskeletal rearrangements and cell extensions. All these trends were drastically modified by TCDD. We hypothesize that, taken together, these results might further clarify the processes responsible for the action of TCDD on the BoHV-1 replication, resulting in enhanced virus production.     

Prediction of phytotoxicity and uptake of metals by models in proposed USEPA 40 CFR part 503 sludge regulations: Comparison with field data for corn and wheat

The United States Environmental Protection Agency (USEPA) has recently (February 6, 1989) proposed the 40 CFR Part 503 regulations which govern sludge use and disposal. The numerical limits on cumulative soil metal loading rates in these regulations were generated through risk assessment analysis based on modeling metal flux through several terrestrial pathways. Field data from a 6300 ha dedicated land application site operated by the Metropolitan Water Reclamation District of Greater Chicago (District) since 1972 indicate that these pathway models do a poor job of predicting bioaccumulation of Cd, Cu, and Zn in corn leaf and grain and wheat grain tissue. The USEPA pathway model does not take soil pH into account and predicts that plant tissue concentration will be linearly related to metal loading rates in soil. District field data indicate that crop tissue metal concentrations are dependent on soil pH and increase at low metal loadings but then become independent of total metal loading rate. No phytotoxicity was observed in corn or wheat despite soil loading rates for Cr, Cu, Ni, and Zn that were 13, 28, 3, and 16 times higher than their respective phytotoxic thresholds predicted by the USEPA pathway model.

     

Using public databases for genomic prediction of tropical maize lines

In this paper, the aims were (a) to test the usefulness of using genomic and phenotypic information from public databases (open access) to predict genetic values for tropical maize inbred lines regarding plant and ear height; (b) to identify how the population structure, the use of optimized training sets (OTSs) and the amount of information originating from public databases affect the predictive ability. Thus, 29 training sets (TSs) were defined considering three diversity panels: the University of São Paulo (USP—validation set (VS)) and the ASSO and USDA North Central Regional Plant Introduction Station (NCRPIS) (external public panels—predictors), which were divided into four scenarios with different TS configurations. We showed that it is possible to use public datasets as a primary TS and that population structure can modify the predictive abilities of GS. In the four scenarios proposed, very large or very small sets did not provide predictive abilities over 0.53 for GS. However, OTSs composed of 250 individuals were sufficient to achieve predictive abilities over this limit.     

Nutritional aspects of second generation soy foods

Samples of 15 second generation soy-based products (n = 3), commercially available, were analyzed for their protein and isoflavone contents and in vitro antioxidant activity, by means of the Folin-Ciocalteu reducing ability, DPPH radical scavenging capacity, and oxygen radical absorbance capacity. Isoflavone identification and quantification were performed by high-performance liquid chromatography. Products containing soy and/or soy-based ingredients represent important sources of protein in addition to the low fat amounts. However, a large variation in isoflavone content and in vitro antioxidant capacity was observed. The isoflavone content varied from 2.4 to 18.1 mg/100 g (FW), and soy kibe and soy sausage presented the highest amounts. Chocolate had the highest antioxidant capacity, but this fact was probably associated with the addition of cocoa liquor, a well-known source of polyphenolics. This study showed that the soy-based foods do not present a significant content of isoflavones when compared with the grain, and their in vitro antioxidant capacity is not related with these compounds but rather to the presence of other phenolics and synthetic antioxidants, such as sodium erythorbate. However, they may represent alternative sources and provide soy protein, isoflavones, and vegetable fat for those who are not ready to eat traditional soy foods.