Intrauterine Neospora caninum inoculation of heifers

Here, we studied the potential of Neospora caninum tachyzoites to infect heifers when administered in utero by artificial insemination via contaminated semen. Eighteen primiparous cyclic heifers were hormonally synchronized and artificially inseminated. Nine of them, which were inseminated with semen containing 10(7) live N. caninum NC-1 isolate-tachyzoites, reacted with seroconversion and a specific IFN-gamma response. Moreover, N. caninum DNA was demonstrated by a nested-PCR in the blood of all nine heifers and in brain, lungs, liver and uterine horn of several of them. In contrast, nine heifers inseminated with tachyzoite-free semen developed no antibody or IFN-gamma responses, and no parasite DNA was detected in blood or organs. At necropsy, viable embryos were detected in one and six of the infected and non-infected heifers, respectively. No specific Neospora DNA was detected in any of the embryos. This study provides evidence that intrauterine inoculation via contaminated semen cause N. caninum infection in cattle.     

A population of murine gammadelta T cells that recognize an inducible MHC class Ib molecule

Although gammadelta T cells are implicated in regulating immune responses, gammadelta T cell-ligand pairs that could mediate such regulatory functions have not been identified. Here, the expression of the major histocompatibility complex (MHC) class Ib T22 and the closely related T10 molecules is shown to be activation-induced, and they confer specificity to about 0.4% of the gammadelta T cells in normal mice. Thus, the increased expression of T22 and/or T10 might trigger immunoregulatory gammadelta T cells during immune responses. Furthermore, the fast on-rates and slow off-rates that characterize this receptor/ligand interaction would compensate for the low ligand stability and suggest a high threshold for gammadelta T cell activation.     

Ecotypes of Italian ryegrass from Swiss permanent grassland outperform current recommended cultivars

Italian ryegrass (Lolium multiflorum Lam. ssp. italicum Volkart ex Schinz et Keller) thrives well in permanent grassland in mild and moist regions of Switzerland. Ecotypes of Italian ryegrass from Swiss permanent meadows have often been used successfully as the base material of breeding programmes. However, their agronomic performance per se has never been studied in detail. Therefore, field trials were conducted to assess the potential of this semi-natural genetic resource for use in breeding. Twenty ecotype populations were collected in different geographical regions in 2003 and seed was increased. Plot trials with 20 ecotype populations were conducted 2005–2007 at three locations, supplemented by row trials at two additional locations, and including four currently recommended cultivars as controls. Average performance in terms of yield, vigour and resistance to snow mould of ecotypes was superior to the cultivars. Depending on the characteristic, between three and 16 of the 20 ecotypes performed significantly better than the cultivars mean. However, resistance against crown rust of all ecotypes was significantly poorer than that of the cultivars. Correlation and regression analysis showed that more eastern and more northern collecting sites harboured better performing ecotypes. However, the most consistent site related factor favouring performance of the ecotypes in terms of yield, vigour, snow mould and Xanthomonas resistance was a low abundance of species which are typical of Arrhenatheretum type meadows. Data from the plot trials were related to results obtained with spaced plants at a single site, either in a seedling nursery or in the greenhouse. Resistance against crown rust was extremely well predicted by spaced plant observations. Xanthomonas resistance observed after artificial inoculation in the greenhouse was also significantly, but less closely correlated with field observations. An early date of ear emergence as observed on spaced plants was associated with high annual yield in the plot trials. It is concluded that in intensively managed habitats, natural selection has resulted in ecotype populations of Italian ryegrass which are highly promising for use in breeding. Individual plant selection for resistance can be expected to efficiently reduce their high susceptibility to crown rust.     

Scanning study of the optical parameters of sandy soddy-steppe soil samples from the southern Ukraine

It was shown that an office scanner can be used for the acquisition of digital images of soil samples and their analysis using the RGB color system. The content and optical density of the humic acids were the main factors determining the color intensity of sandy soils. With all the other factors being constant, the increase in the content of clay particles resulted in a decrease in the color intensity of the sandy soils, whereas a decrease in the content of the coarse sand increased the color intensity. The content of mobile iron had the least significant effect on the color of the sandy soils.     

Crystal structure of a gammadelta T cell receptor ligand T22: a truncated MHC-like fold

Murine T10 and T22 are highly related nonclassical major histocompatibility complex (MHC) class Ib proteins that bind to certain gammadelta T cell receptors (TCRs) in the absence of other components. The crystal structure of T22b at 3.1 angstroms reveals similarities to MHC class I molecules, but one side of the normal peptide-binding groove is severely truncated, which allows direct access to the beta-sheet floor. Potential gammadelta TCR-binding sites can be inferred from functional mapping of T10 and T22 point mutants and allelic variants. Thus, T22 represents an unusual variant of the MHC-like fold and indicates that gammadelta and alphabeta TCRs interact differently with their respective MHC ligands.     

Dating chicks: Calibration and discrimination in a nonlinear multivariate hierarchical growth model

The motivation for this work was to investigate the possibility of accurately determining the age of a tern chick using easily obtained body measurements. We describe the construction of a nonlinear multivariate hierarchical model for chick growth and show how it can be estimated using Markov chain Monte Carlo techniques. A simple extension of the analysis allows for estimation of the ages of unknown chicks. Posterior distributions of the unknown ages are derived, so that the accuracy of age determination can be examined. We further extend our model and analysis to include the possibility that chicks fall into distinct groups with different growth characteristics. The technique is illustrated using data on the weight and wing length of black-fronted terns from the Ohau River, New Zealand. It is found that dating to within one day is possible, but only in some areas of the data space. The concept of “braiding” of multivariate growth curves is introduced to explain the varying accuracy of age determination.     

Experience in a breeding program to create a flock of sur Karakul sheep of the new Surkhan Darya type

To increase the production of sur karakul fur of the Surkhan Darya intrabreed type, regularities in the inheritance of colors in progeny have been studied. Both with homogeneous and heterogeneous breeding of ewes and stud rams of bronze, amber, and platinum colors, a high heredity of bronze and platinum colors is noted. The color of rams has a greater effect on inheritance of colors.