Serological characterization of the new genotype E of small ruminant lentivirus in roccaverano goat flocks

Maedi visna virus (MVV) and caprine arthritis encephalitis virus (CAEV) are a heterogeneous group of infectious agents affecting sheep and goats. Due to their natural cross-species infection they are referred to as small-ruminant lentiviruses (SRLV). Recently a new genetic cluster, highly divergent from MVV and CAEV was identified in the north-west part of Italy. A panel of genotype E specific antigens was developed and evaluated in flocks infected with B1 and E strains. The results clearly indicate that a strain specific antigen is required to correctly identify animals infected with different genotypes.

     

Cytokine mRNA expression and pathological findings in pigs inoculated with African swine fever virus (E-70) deleted on A238L

African swine fever virus (ASFV) induces a variety of immune responses and clinical forms in domestic pigs. As it is the only member of the Asfarviridae family, ASFV encodes many novel genes not encoded by other virus families. Among these genes, A238L may regulate the synthesis of pro-inflammatory cytokines, controlled mainly by NFkappaB and NFAT pathways. In this study, we inoculated two groups of pigs, one with the ASFV highly virulent E-70 isolate, deleted on A238L gene, and the other group with the parental E-70 isolate. No significant differences were observed in the clinical signs or pathology between both groups. However, the TNF-alpha mRNA expression was strongly enhanced in the PBMC from pigs inoculated with the virus deleted in A238L, reinforcing the role of the A238L gene in the inhibition of the NFkappaB pathway of expression of cytokines. No up-regulation of pro-inflammatory cytokines was observed in the PBMC of animals inoculated with the E-70 isolate, even though apoptosis and haemorrhages were evident and might be related to the presence of bystander monocyte-macrophages expressing these cytokines. Other studies using ASFV deleted in other genes inoculated in the natural hosts should be performed to gain further insight into the role of these genes in the pathogenesis of ASF.     

A Morphological Study of Cultured Endodermal Cells of Chick Embryo: Characteristics of Adhesion, Spreading and Locomotion

A study is made of the morphological characteristics of the endodermic cells of the stage 5 chick embryo by means of in vitro cell culture techniques. The scanning electron microscope revealed that the endodermic cells in cultures were rounded, tended to be smooth and had few blebs and microvilli. Regarding cell projections typical of culture cells, such as filopodia, lamellipodia and pseudopodia, there was a noteworthy scarcity after 12 h growth, although greater cellular activity was observed at 24 h, characterized by the presence of filopodia and an ability of the cells to form clusters on the substratum. These facts show the morphological and adhesion movements of the endodermal cells studied to be related mainly with the presence of filopodia as the most abundant cell projections.     

Molecular evolution of herbicide resistance to phytoene desaturase inhibitors in Hydrilla verticillata and its potential use to generate herbicide-resistant crops

Hydrilla [Hydrilla verticillata (Lf) Royle] is one of the most serious invasive aquatic weed problems in the USA. This plant possesses numerous mechanisms of vegetative reproduction that enable it to spread very rapidly. Management of this weed has been achieved by the systemic treatment of water bodies with the herbicide fluridone. At least three dioecious fluridone-resistant biotypes of hydrilla with two- to fivefold higher resistance to the herbicide than the wild-type have been identified. Resistance is the result of one of three independent somatic mutations at the arginine 304 codon of the gene encoding phytoene desaturase, the molecular target site of fluridone. The specific activities of the three purified phytoene desaturase variants are similar to the wild-type enzyme. The appearance of these herbicide-resistant biotypes may jeopardize the ability to control the spread of this non-indigenous species to other water bodies in the southern USA. The objective of this paper is to provide general information about the biology and physiology of this aquatic weed in relation to its recent development of resistance to the herbicide fluridone, and to discuss how this discovery might lead to a new generation of herbicide-resistant crops.     

Epidemiological pattern and risk factors associated with bovine viral-diarrhoea virus (BVDV) infection in a non-vaccinated dairy-cattle population from the Asturias region of Spain

A survey of bovine viral-diarrhoea virus (BVDV) infection was carried out in a non-vaccinated cattle population from the Asturias region of Spain in 1997 to assess seroprevalence and identify risk factors associated with infection. Twenty-eight herds were included; 529 cows were bled. Information regarding the herd and each animal sampled were recorded through a personal interview with the farmer. The true prevalence was estimated to be 21%. According to the antibody-age profiles and the herd-management characteristics, no persistently infected animals were suspected at that time within the herds sampled. Random-effects logistic regression found two major factors associated with seropositivity: age and cow origin. Results suggested that BVDV infection could be controlled in that area by livestock-trade control (without vaccines). In addition, an increasing risk of abortion was not observed when cows were seropositive to both BVDV and Neospora caninum infections.     

Type II Supernova Matter in a Silicon Carbide Grain from the Murchison Meteorite

The circumstellar silicon carbide (SiC) grain X57 from the Murchison meteorite contains large amounts of radiogenic calcium-44 (20 times its solar system abundance) and has an anomalous silicon isotopic composition, different from other circumstellar SiC grains. Its inferred initial 44Ti/Si and 44Ti/48Ti ratios are 1.6 x 10(-4) and 0.37. In addition, it contains radiogenic magnesium-26; the inferred initial 26Al/27Al ratio is 0.11. The isotopic and elemental data of X57 can be explained by selective mixing of matter from different zones of a typical type II supernova of 25 solar masses during its explosion. The high 44Ti/Si ratio requires contributions from the innermost nickel zone of the supernova to the SiC condensation site, as similarly suggested by astronomical observations.     

Correlation of lycopene measured by HPLC with the L, a, b color readings of a hydroponic tomato and the relationship of maturity with color and lycopene content

Tomatoes (Lycopersicon esculentum cv. Laura) were separated, according to the ripening stage, by a sensory panel into seven groups, and color was measured on the tomato surface with a Minolta Chroma meter. The L, a, b, hue, chroma, and lycopene content were plotted against the maturity stages of the tomatoes, and several good correlations were found. The a/b ratio and the lycopene content were the parameters that allowed six of seven maturity groups in the tomato to be statistically distinguished. The lycopene content, measured by HPLC, was also correlated with the color measurements, and the a, a/b, and (a/b)(2) color factors produced the best regressions. An estimation of the lycopene content in tomatoes can be achieved by using a portable chroma meter, with a possible field usage application. Equations to calculate the lycopene content of tomatoes based on the color readings are reported.     

Estimation of phosphate adsorption by Acrisols of western Spain from electrical conductivity of potassium dihydrogen phosphate extracts of soil

Estimation of the phosphate adsorption capacity in highly weathered acid soils is crucial for adopting appropriate phosphate fertilization practices. In this work, the salt sorption effect was used to develop a method for estimating phosphate adsorption capacity from the decrease in electrical conductivity of a potassium dihydrogen phosphate solution brought in contact with acidic soil samples from surface and subsurface horizons of Acrisols. The method is fast and simple and requires only the use of a conductimeter.