Effect of climatic factors on urinary cortisol and peripheral blood leukocytes in lambs grazing on a semi-natural grassland in the Hokuriku District of Japan

The effects of climatic factors on stress and immune functions of grazing lambs in summer and autumn in the Hokuriku District of Japan were evaluated by determining urinary cortisol (U-COR) levels and peripheral blood leukocyte populations and comparing those with lambs kept indoors. Two groups of five lambs, consisting of those grazed on a semi-natural grassland (GRL) and those housed indoors in a domestic animal shelter (INL), were maintained at from July to October. The temperature–humidity index at each location was indicative of heat stress during summer; however, the U-COR elevation was not observed in both groups. The elevation was observed in GRL in autumn and was higher than INL in October. Climatic conditions in autumn were characterized by high humidity and a sudden drop in temperature. U-COR was positively correlated with the relative humidity. The GRL was exposed to low-nutrient conditions for a relatively long time. The CD4⁺/CD8⁺ T cell ratio in GRL decreased in October. Subsequently, the total leucocyte, including granulocytes, monocytes, and lymphocytes, sharply increased. The responses indicated an immune deficiency caused by immunosuppression because of a low nutrition caused by grazing and high-stress conditions in autumn.     

Combining ability under drought stress relative to SSR diversity in common wheat

Eight-parental diallel cross and SSR molecular markers were used to determine the combining ability of common wheat lines grown under well-watered (WW) and water-stress (WS) conditions. Analysis of variance of yield indicated highly significant differences among the progenies. General combining ability (GCA) determined most of the differences among the crosses. Specific combing ability (SCA) was also significant but less important. The estimates of GCA effects indicated that one line was the best general combiner for grain yield under drought. Neis genetic distance, measured using SSR markers, differed from 0.20 to 0.48 among the eight genotypes. The correlation of Neis genetic distance with SCA for grain yield and heterosis ranged from 0.4 to 0.5. These results indicate that the level of SCA and heterosis depends on the level of genetic diversity between the wheat genotypes examined. Microsatellite markers were effective in predicting the mean and the variance of SCA in various cultivars combinations. However, selection of crosses solely on microsatellite data would miss superior combinations.     

Effect of high temperature on the production of 2n pollen grains in diploid roses and obtaining tetraploids via unilateral polyploidization

To integrate the gene pool of a wild species (primarily diploid) into a cultivated pool (primarily tetraploid), a crossing between a dihaploid cultivated rose and a hybrid of Rosa wichurana allowed to obtain interspecific diploid hybrids that produced 2n pollen grains. A return to a tetraploid level sought by breeders can then be considered using sexual polyploidization, obtained by crossing a tetraploid cultivated rose with these hybrids. Application of a high‐temperature regime led to a small but significant increase in the percentage of 2n pollen grains in these hybrids of up to 4.6%. This result was obtained by applying high temperatures close to 32°C during the day to plants cultivated in a glasshouse during recurrent cycles of bloom. Crosses were made between an unreleased tetraploid hybrid tea rose, as a female, and the diploid hybrid that produces the most 2n pollen grains. Tetraploid (42.1%) and triploid (57.9%) offspring were obtained. The use of these 2n pollen grains of the first division restitution type should facilitate the introgression of complex traits of interest.     

Genetic diversity of Czech ‘Candidatus Phytoplasma mali’ strains based on multilocus gene analyses

In several European countries apple trees are affected by apple proliferation disease, which is usually associated with the presence of ‘Candidatus Phytoplasma mali’. During 2010, samples from several apple trees displaying proliferation symptoms were collected throughout the Czech Republic to verify identity of phytoplasmas detected in association with the disease. The majority of the 74 apple trees examined using molecular tools were positive for ‘Ca. P. mali’ presence. The 16S–23S ribosomal genes, the ribosomal protein genes and the nitroreductase and rhodonase like genes were then studied to verify phytoplasma strain variability on multigenic bases. Two RFLP profiles and correspondingly two genetic lineages were found in the PCR-amplified fragments covering the 16S–23S rDNA spacer region. ‘Ca. P. mali’ strains belonging to rpX-A subgroup were identified in the majority of the apple tree sampled, whereas phytoplasmas belonging to the rpX-B subgroup were distributed sporadically. The apple proliferation subtypes AP-15 and AT-2 exhibited nearly equal occurrence; the AT-1 subtype and a mixture of the two or all three of the AP subtypes were infrequently found. The PCR/RFLP results were confirmed by nucleotide sequence analyses of selected ‘Ca. P. mali’ strains.     

Effects of dietary supplementation of nickel and nickel-zinc on femoral bone structure in rabbits

Background

Nickel (Ni) and zinc (Zn) are trace elements present at low concentrations in agroecosystems. Nickel, however, may have toxic effects on living organisms and is often considered as a contaminant. This study reports the effect of peroral administrated Ni or a combination of Ni and Zn on femoral bone structure in rabbits.

Methods

One month-old female rabbits were divided into three groups of five animals each. Group 1 rabbits were fed a granular feed mixture with addition of 35 g NiCl₂ per 100 kg of mixture for 90 days. In group 2, animals were fed a mixture containing 35 g NiCl₂ and 30 g ZnCl₂ per 100 kg of mixture. Group 3 without administration of additional Ni or Zn served as control. After the 90-day experimental period, femoral length, femoral weight and histological structure of the femur were analyzed and compared.

Results

The results did not indicate a statistically significant difference in either femoral length or weight between the two experimental groups and the control group. Also, differences in qualitative histological characteristics of the femora among rabbits from the three groups were absent, except for a fewer number of secondary osteons found in the animals of groups 1 and 2. However, values for vascular canal parameters of primary osteons were significantly lower in group 1 than in the control one. Peroral administration of a combination of Ni and Zn (group 2) led to a significant decreased size of the secondary osteons.

Conclusions

The study indicates that dietary supplementation of Ni (35 g NiCl₂ per 100 kg of feed mixture) and Ni-Zn combination (35 g NiCl₂ and 30 g ZnCl₂ per 100 kg of the mixture) affects the microstructure of compact bone tissue in young rabbits.