Co-existence of classical scrapie and Nor98 in a sheep from an Italian outbreak

Nor98 is an atypical scrapie strain characterized by a molecular pattern and brain distribution of the pathological prion protein (PrP^Sc) different from classical scrapie. In Italy, 69 atypical cases have been identified so far and all were characterized as Nor98 strain. In this paper we report an unusual case in a sheep which showed immunohistochemical and molecular features of PrP^Sc different from the other atypical cases. The sheep was from an outbreak where the index and the other four cases were affected by classical scrapie. Histopathological, immunohistochemical and Western blot analyses on the brain of the unusual case revealed the simultaneous presence of pathological features characteristic of Nor98 and classical scrapie. Interestingly, the prevalent disease phenotype in the brainstem was classical scrapie-like, while in the cerebral cortex and cerebellum the Nor98 phenotype was dominant. The sub-mandibular lymph node was positive and showed a PrP^Sc molecular pattern referable to classical scrapie. The PrP genotype was AL₁₄₁RQ/AF₁₄₁RQ. Taken together, the occurrence of classical scrapie in the outbreak, the PrP genotype, the involvement of different cellular targets in the brain and the pathological and molecular PrP^Sc features observed suggest that this unusual case may result from the co-existence of Nor98 and classical scrapie.     

Nature of the ultraviolet absorber in the venus clouds: inferences based on pioneer venus data

Several photometric measurements of Venus made from the Pioneer Venus orbiter and probes indicate that solar near-ultraviolet radiation is being absorbed throughout much of the main cloud region, but little above the clouds or within the first one or two optical depths. Radiative transfer calculations were carried out to simulate both Pioneer Venus and ground-based data for a number of proposed cloud compositions. This comparison rules out models invoking nitrogen dioxide, meteoritic material, and volatile metals as the source of the ultraviolet absorption. Models involving either small ( approximately 1 micrometer) or large ( approximately 10 micrometers) sulfur particles have some serious difficulties, while ones invoking sulfur dioxide gas appear to be promising.     

Photometry from voyager 2: initial results from the uranian atmosphere, satellites, and rings

The Voyager 2 photopolarimeter successfully completed the Uranus encounter, acquiring new data on the planet's atmosphere, its principal satellites, and its ring system. Spatially resolved photometry of the atmosphere at 0.27 micrometer shows no enhancement in absorption toward the pole, unlike the case for Jupiter and Saturn. Stellar occultation measurements indicate the temperature at the 1-millibar level over the north pole is near 90 kelvins. The geometric albedos of the five large satellites of Uranus were measured at 0.27 and 0.75 micrometer and indicate the presence of low albedo, spetrally flat absorbing material. Titania seems to have a fluffy surface, as indicated by its phase curve. The nine ground-based rings were detected, and their internal structure, optical depths, and positions were determined. The sharp edges of the in ring made it possible to measure its edge thickness (less than 150 meters) and particle sizes (less than 30 meters); little or no dust was detcted. New narrow rings and partial rings (arcs) were measured, and the narrow component of the eta ring was found to be discontinuous.     

Fertilization strategies on cultivars of globe artichoke: Effects on yield and quality performance

This paper refers on the yields and productive aspects of mineral and foliar nutrition of globe artichoke plants (cv. ‘Opal’ and ‘Madrigal’). Marketable yields were investigated in response to different nitrogen rates and foliar applications of biostimulating products. Field experiments were conducted over two seasons on an alluvial salty-clay soil in sub-humid climate conditions. Analyzed traits differed between years because of the age of plants while the lowest nitrogen rate and foliar spraying of biostimulants influenced significantly head weight, dry matter, and Soil Plant Analysis Division (SPAD) index. Biostimulants induced longer cultural cycle and heads lighter in weight. Cultivar ‘Madrigal’ was most productive than ‘Opal’, both in number (26.28% higher) and in weight (28.51%) of total heads. The two-year investigation showed that the synergic action was effective in improving some of the investigated productive traits of globe artichoke.     

Glycoalkaloid content and chemical composition of potatoes improved with nonconventional breeding approaches

This paper reports the results of chemical analyses performed on two distinct groups of new potato genotypes. The first group contained five clones transformed with the gene ech42 encoding for an endochitinase. The second included 21 interspecific hybrids between the cultivated potato Solanum tuberosum and the wild species S. commersonii, obtained either by somatic fusion or by sexual hybridization. Tubers from transgenic plants were analyzed for several morphological and biochemical parameters to ascertain the substantial equivalence between the transgenic genotypes and the original cultivar Désirée. The interspecific hybrids were analyzed for the same parameters in order to identify genotypes with novel improved chemical characteristics and with low levels of glycoalkaloids deriving from the wild species and potentially hazardous to human health. For transgenic tubers, the results provided evidence that indicates the substantial equivalence between the transgenic genotypes and the cultivated control for the considered traits. The results suggest that chitinase gene insertion did not alter other metabolic pathways of potato tubers and did not cause unintentional pleiotropic effects. As far as interspecific hybrids are concerned, wide variability for all of the parameters analyzed was found. For some useful traits (e.g., soluble solids and proteins, dry matter content) the interspecific hybrids performed better than both the cultivated control and the wild species. In a number of genotypes, glycoalkaloid levels were close to or lower than those of the control varieties, suggesting that selection for low glycoalkaloid content is possible. The results also indicated that glycoalkaloids from S. commersonii may be lost rapidly. Indeed, some hybrids were found to have the same glycoalkaloid profile as S. tuberosum. Finally, the results showed that among the parameters considered, glycoalkaloid content is the most sensitive to variation. Therefore, glycoalkaloid determination should be used for routine control of genotypes produced by interspecific hybridization.     

Correction to: A prioritised inventory of crop wild relatives and wild harvested plants of Tunisia

Genetic Resources and Crop Evolution -     

Venus: mass, gravity field, atmosphere, and ionosphere as measured by the mariner 10 dual-frequency radio system

Analysis of the Doppler tracking data near encounter yields a value for the ratio of the mass of the sun to that of Venus of 408,523.9 +/- 1.2, which is in good agreement with prior determinations based on data from Mariner 2 and Mariner 5. Preliminary analysis indicates that the magnitudes of the fractional differences in the principal moments of inertia of Venus are no larger than 10(-4), given that the effects of gravity-field harmonics higher than the second are negligible. Additional analysis is needed to determine the influence of the higher order harmonics on this bound. Four distinct temperature inversions exist at altitudes of 56, 58, 61, and 63 kilometers. The X-band signal was much more rapidly attenuated than the S-band signal and disappeared completely at 52-kilometer altitude. The nightside ionosphere consists of two layers having a peak density of 10(4) electrons per cubic centimeter at altitudes of 140 and 120 kilometers. The dayside ionosphere has a peak density of 3 X 10(5) electrons per cubic centimeter at an altitude of 145 kilometers. The electron number density observed at higher altitudes was ten times less than that observed by Mariner 5, and no strong evidence for a well-defined plasmapause was found.