Characterization of age-related changes in bovine CD8+ T-cells

Evaluation of the changes induced by immunological interventions requires a baseline against which to compare those changes. The age-related changes in the CD8(+) T-cell population of cattle were studied. The results indicate that CD8(+) T-cells could be divided into γ/δ TCR1(+) and γ/δ TCR1(-) according to their expression of the γ/δ T-cell receptor. As a proportion, the CD8(+) γ/δ TCR1(+) population appears to increase with age. Within the CD8(+)γ/δ TCR1(-) a population of cells expressing a profile of surface molecules previously associated with effector memory T cells (CD45RO(+), CD62L(-), CD27(-), CD45RA(-) and CD28(-)) increases with age. Furthermore, a parallel increase with age in the proportion of CD8(+)CD45RO(+) T cells that express the cytotoxic granule protein perforin was observed. In peripheral tissues, namely lungs, it was found that the majority of CD8(+) T cells present expressed a phenotype indicative of previously primed T cells (high expression of CD45RO and perforin). In contrast, only a small population of memory CD8(+) T cells was present in lymphoid tissue where most of the CD8(+) T cells expressed a na?ve phenotype. In conclusion, in cattle, like in human, CD8(+) T cells that express a phenotype associated with antigen experience accumulate with age that may play a role in immunocompetence as the individual ages.     

Tumoricidal effect of interleukin-2-activated killer cells in canines

We investigated the effect of both partially purified (TCGF) and recombinant interleukin-2 (rIL-2) on the tumor-directed cytotoxic activity of canine peripheral blood mononuclear cells (PBMC) using three normal canines. No cytotoxic activity was displayed by unstimulated effector cells at 3 h of incubation; however, the cytotoxic effect was observed in a 16-h assay. PBMC of all canines displayed significant levels of lytic activity after stimulation for 4 to 7 days with both types of IL-2 against a variety of allogeneic and xenogeneic neoplastic cells in 3-h 51Cr release assay. The cytotoxic activity of cultured cells increased proportionally in the 16-h assays. Morphological examination of the May-Grünwald and Giemsa stained cytocentrifuged slides of cultured cells on each day of assay showed an increase in large granular lymphocytes (LGLs) beginning on day 4 and reaching a peak on day 7 of culture.     

Detection of genes encoding for virulence and adherence factors in Escherichia coli isolated in slaughtered Sarda breed sheep

In order to investigate the pathogenic profile of Escherichia coli hosted in “Sarda” sheep, autochthonous race present in Sardinia, thirty-seven E. coli strains collected from different sources (fleeces, carcass swabs and gut mucosa) of pre-chill slaughtered sheep (ewes and lambs) were serotyped using pheno- and genotypic methods. Furthermore, the presence of genes encoding for virulence factors and mediating for localized mucosal adherence factors was investigated, and pulsed-field gel electrophoresis (PFGE) characterization was performed.     

Recombinant adenovirus expressing the haemagglutinin of peste des petits ruminants virus (PPRV) protects goats against challenge with pathogenic virus; a DIVA vaccine for PPR

Peste des petits ruminants virus (PPRV) is a morbillivirus that can cause severe disease in sheep and goats, characterised by pyrexia, pneumo-enteritis, and gastritis. The socio-economic burden of the disease is increasing in underdeveloped countries, with poor livestock keepers being affected the most. Current vaccines consist of cell-culture attenuated strains of PPRV, which induce a similar antibody profile to that induced by natural infection. Generation of a vaccine that enables differentiation of infected from vaccinated animals (DIVA) would benefit PPR control and eradication programmes, particularly in the later stages of an eradication campaign and for countries where the disease is not endemic. In order to create a vaccine that would enable infected animals to be distinguished from vaccinated ones (DIVA vaccine), we have evaluated the immunogenicity of recombinant fowlpox (FP) and replication-defective recombinant human adenovirus 5 (Ad), expressing PPRV F and H proteins, in goats. The Ad constructs induced higher levels of virus-specific and neutralising antibodies, and primed greater numbers of CD8⁺ T cells than the FP-vectored vaccines. Importantly, a single dose of Ad-H, with or without the addition of Ad expressing ovine granulocyte macrophage colony-stimulating factor and/or ovine interleukin-2, not only induced strong antibody and cell-mediated immunity but also completely protected goats against challenge with virulent PPRV, 4 months after vaccination. Replication-defective Ad-H therefore offers the possibility of an effective DIVA vaccine.     

A strategy to identify sources of quantitative resistance in pathosystems involving disease escape and physiological resistance: the case study of rice sheath blight

An epidemiology‐based strategy using rice sheath blight (ShB) as a biological model was developed that enables identification of sources of resistance. A set of 163 cultivated rice genotypes, including genotypes which had been reported to express partial resistance to ShB, and a few genotypes reported as very susceptible, were assessed using two complementary methods. First, microfield experiments allowed measurement of disease intensification at, and spread from, inoculated sources, along with morphological traits of each genotype. Secondly, detached tiller tests allowed measurement of the physiological resistance to the disease under conditions where morphology does not come into play. Multivariate analysis involving hierarchical cluster analysis, followed by multiple correspondence analysis, indicated that levels of physiological resistance, groups of plant morphology and disease levels in microfields were associated. Results from logistic regressions further indicated that a decreased number of lesions measured on detached tillers increased the odds of a rice genotype belonging to the group with low disease intensity in microfields. The combined results from microfield and detached tiller tests allowed identification of 23 genotypes with low level of disease intensity, which may be used as sources of resistance to ShB in breeding programmes. The results suggest that this strategy, which combines the crop stand and the individual tiller scales, may be applied to the identification of sources of resistance to a range of diseases with similar life cycle traits.     

Regulation of the oocyte-to-zygote transition

Oocytes, the female germ cells, contain all the messenger RNAs necessary to start a new life but typically wait until fertilization to begin development. The transition from oocyte to fertilized egg (zygote) involves many changes, including protein synthesis, protein and RNA degradation, and organelle remodeling. These changes occur concurrently with the meiotic divisions that produce the haploid maternal genome. Accumulating evidence indicates that the cell-cycle regulators that control the meiotic divisions also regulate the many changes that accompany the oocyte-to-zygote transition. We suggest that the meiotic machinery functions as an internal pacemaker that propels oocytes toward embryogenesis.     

Impact of destroying the structure of model gels on volatile release

The release of a strawberry aroma from different composite gels taken as models of fruit preparations and from a sucrose solution was investigated. The composition of the model systems differed with regard to the gelling agent, either pectin or carrageenan, and to the rigidity of the gel. With the use of atmospheric pressure chemical ionization-mass spectrometry, the release profiles of the aroma compounds were determined under stirring. At the same time, purge and trap measurements were performed to determine the release profiles of the aroma compounds without stirring. The comparison of the patterns obtained using these two complementary methods made it possible to determine how the structure of the matrix, the mechanical treatment, and the properties of the aroma compound affect aroma release. A far greater proportion of the aroma compounds was retained in the fruit preparation systems than in the sucrose solution. The different release profiles could be interpreted in terms of the volatility of the aroma compounds and of their diffusion through the gels.     

Pharmacokinetics and pharmacodynamics of intravenous and transdermal flunixin meglumine in meat goats

The aim of this study was to determine the pharmacokinetics and prostaglandin E₂ (PGE₂) synthesis inhibiting effects of intravenous (IV) and transdermal (TD) flunixin meglumine in eight adult female Boer goats. A dose of 2.2 mg/kg was administered intravenously (IV) and 3.3 mg/kg administered TD using a cross‐over design. Plasma flunixin concentrations were measured by LC‐MS/MS. Prostaglandin E₂ concentrations were determined using a commercially available ELISA. Pharmacokinetic (PK) analysis was performed using noncompartmental methods. Plasma PGE₂ concentrations decreased after flunixin meglumine for both routes of administration. Mean λ_z‐HL after IV administration was 6.032 hr (range 4.735–9.244 hr) resulting from a mean V_z of 584.1 ml/kg (range, 357.1–1,092 ml/kg) and plasma clearance of 67.11 ml kg^?1 hr^?1 (range, 45.57–82.35 ml kg^?1 hr^?1). The mean C_max, T_max, and λ_z‐HL for flunixin following TD administration was 0.134 μg/ml (range, 0.050–0.188 μg/ml), 11.41 hr (range, 6.00–36.00 hr), and 43.12 hr (15.98–62.49 hr), respectively. The mean bioavailability for TD flunixin was calculated as 24.76%. The mean 80% inhibitory concentration (IC₈₀) of PGE₂ by flunixin meglumine was 0.28 μg/ml (range, 0.08–0.69 μg/ml) and was only achieved with IV formulation of flunixin in this study. The PK results support clinical studies to examine the efficacy of TD flunixin in goats. Determining the systemic effects of flunixin‐mediated PGE₂ suppression in goats is also warranted.