Development of novel clubroot resistant rapeseed lines (Brassica napus L.) effective against Japanese field isolates by marker assisted selection

Clubroot is an important disease infectible to cruciferous plants and a major threat to rapeseed production in Japan. However, no clubroot resistant rapeseed cultivars have been released. We surveyed pathotype variation of six isolates collected from rapeseed fields and found they were classified as pathotype groups 2 and 4 using Japanese F₁ Chinese cabbage cultivars. We produced the resynthesized clubroot resistant Brassica napus harboring two resistant loci, Crr1 and Crr2, by interspecific crossing and developed resistant rapeseed lines for southern and northern regions by marker-assisted selection and backcrossing. We improved the DNA marker for erucic acid content to remove linkage drag between Crr1 and high erucic acid content and successfully selected lines with clubroot resistance and zero erucic acid for northern regions. A novel line, ‘Tohoku No. 106’, suitable for southern regions showed stable resistance against all six isolates and high performance in infested fields. We conclude that Crr1 and Crr2 are important genes for CR rapeseed breeding and marker-assisted selection is effective in improving clubroot resistance.     

Proliferation of canine intervertebral disk chondrocytes in three-dimensional alginate microsphere culture

Proliferation of chondrocytes from nucleus pulposus (NP) and anulus fibrosus (AF) was confirmed in three-dimensional culture using alginate microspheres. Cells isolated from NP and AF were incorporated in microspheres and cultured for 14 days. Round mononuclear cells of 20-25 microm in diameter proliferated and formed aggregates. At day 14, alcian blue positive matrix surrounded the proliferating cells. The cells had cytoplasmic vacuoles stained positively by toluidine blue. On electron microscopy, the cells contained proteoglycan vacuoles and lipid droplets in the cytoplasm and synthesized collagen fibrils and electron dense granules surrounding the cell. These features of the cells were characteristic for chondrocytes. This culture system should be useful to further investigate metabolic activities of intervertebral disk chondrocytes.     

Application of single‐step genomic best linear unbiased prediction with a multiple‐lactation random regression test‐day model for Japanese Holsteins

This study aimed to evaluate a validation reliability of single‐step genomic best linear unbiased prediction (ssGBLUP) with a multiple‐lactation random regression test‐day model and investigate an effect of adding genotyped cows on the reliability. Two data sets for test‐day records from the first three lactations were used: full data from February 1975 to December 2015 (60 850 534 records from 2 853 810 cows) and reduced data cut off in 2011 (53 091 066 records from 2 502 307 cows). We used marker genotypes of 4480 bulls and 608 cows. Genomic enhanced breeding values (GEBV) of 305‐day milk yield in all the lactations were estimated for at least 535 young bulls using two marker data sets: bull genotypes only and both bulls and cows genotypes. The realized reliability (R²) from linear regression analysis was used as an indicator of validation reliability. Using only genotyped bulls, R² was ranged from 0.41 to 0.46 and it was always higher than parent averages. The very similar R² were observed when genotyped cows were added. An application of ssGBLUP to a multiple‐lactation random regression model is feasible and adding a limited number of genotyped cows has no significant effect on reliability of GEBV for genotyped bulls.     

Sex and age differences in meat composition of Yeso sika deer (Cervus nippon yesoensis) reared for a short period after capture in the wild

Yeso sika deer captured in winter around Lake Akan in Hokkaido were reared for 8–10 months at Tokyo University of Agriculture in Abashiri. Six 1‐year‐old females and males and six 2‐year‐old or older (adult) females and males were slaughtered and their carcasses were processed. The chemical composition, mineral contents and fatty acid composition of the loin were measured. No marked influence of gender or age was noted in the chemical composition of loin. In the mineral contents, significant differences were noted. The potassium and sulfur contents were lower and the sodium content was higher in adult deer meat (P < 0.05, respectively) and the potassium content was higher in male deer meat (P < 0.05). Arsenic, cadmium or lead were not detected. In the unsaturated fatty acid, a significant interaction was detected (P < 0.05), and it was high in 1‐year‐old female deer meat and low in 1‐year‐old male deer meat. Significant gender or age differences were noted only in the mineral contents in the loin of deer reared for a short period after capture.     

ULTRASONOGRAPHIC APPEARANCE OF CHRONIC HYPERTROPHIC PYLORIC GASTROPATHY IN THE DOG

Chronic hypertrophic pyloric gastropathy was diagnosed using ultrasound in six dogs that were presented for chronic vomiting. An evenly thick hypoechoic layer surrounding the pyloric lumen was visualized ultrasonographically in dogs with grades 1 or 2 chronic hypertrophic pyloric gastropathy. This was histologically found to correspond with a thickened muscular layer. Gastric wall thickness was greater than or equal to 9 mm in all six dogs. In dogs with grade 1 or 2 chronic hypertrophic pyloric gastropathy, the hypoechoic muscular layer was greater than or equal to 4 mm.     

Temporal dynamic changes in synthesis of chondroitin sulfate isomers in canine articular chondrocyte culture

To investigate temporal dynamic changes in the synthesis of chondroitin 6-sulfate (CS6) and chondroitin 4-sulfate (CS4) in vitro, normal articular cartilage of femoral heads was harvested from three dogs. Chondrocytes were isolated and cultured in alginate microspheres for 21 days. On days 7, 14 and 21, DNA content was quantified by fluorometric assay using Hoechst 33258. On days 14 and 21, proteoglycans were extracted, and the amounts of CS6 and CS4 were quantified after chondroitinase ABC digestion using capillary electrophoresis. The DNA content and amounts of CS6 and CS4 increased during the culture period. The amounts of CS6 and CS4 divided by DNA content revealed that the synthesis of CS6 was more up-regulated than CS4.     

Analysis of mitochondrial DNA of an endangered beech species,Fagus hayatae Palibin ex Hayata

Mitochondrial DNA restriction fragment length polymorphisms were used to examine cytoplasmic diversity within a relic-like population of Fagus hayatae, located in northern Taiwan. Fifteen trees were surveyed for three restriction endonucleases (BamHI, EcoRI and HindIII) and five mitochondrial gene probes (atpA, atp6, atp9, coxI and coxII). The analysis failed to reveal any polymorphisms, an observation that suggests cytoplasmic uniformity in the F. hayatae population examined. It is also interesting to note that the chondriome type of our F. hayatae samples is very close to that characteristic of F. crenata populations in the southernmost area of Japan.     

Changes in petiole hydraulic properties and leaf water flow in birch and oak saplings in a CO2-enriched atmosphere

Water relations in woody species are intimately related to xylem hydraulic properties. High CO(2) concentrations ([CO(2)]) generally decrease transpiration and stomatal conductance (g(s)), but there is little information about the effect of atmospheric [CO(2)] on xylem hydraulic properties. To determine the relationship between water flow and hydraulic structure at high [CO(2)], we investigated responses of sun and shade leaves of 4-year-old saplings of diffuse-porous Betula maximowicziana Regel and ring-porous Quercus mongolica Fisch. ex Ledeb. ssp. crispula (Blume) Menitsky grown on fertile brown forest soil or infertile volcanic ash soil and exposed to 500 micromol CO(2) mol(-1) for 3 years. Regardless of species and soil type, elevated [CO(2)] consistently decreased water flow (i.e., g(s) and leaf-specific hydraulic conductivity) and total vessel area of the petiole in sun leaves; however, it had no effect on these parameters in shade leaves, perhaps because g(s) of shade leaves was already low. Changes in water flow at elevated [CO(2)] were associated with changes in petiole hydraulic properties.     

Characteristics of the temperature coefficient, Q 10, for the respiration of non-photosynthetic organs and soils of forest ecosystems

The temperature coefficient, Q ₁₀ (fractional change in rate with a 10°C increase in temperature) describes the temperature sensitivity of soils, roots, and stems, as well as their possible performance in global warming processes. It is also a necessary parameter for the estimation of total CO₂ efflux from each element. A number of studies have focused on Q ₁₀ values to date; however, their conclusions are not universal and do not always agree. A review of these reported Q ₁₀ values therefore becomes necessary and important for a global understanding of the temperature sensitivity of different forest types and elements. The aims of our present paper are, first, to find the frequency distribution pattern of soils, roots, and stems (branches) and compare their temperature sensitivity; then, to find the Q ₁₀ differences between conifer and deciduous tree species and the effect of methodology on Q ₁₀ values; finally we want to give a perspective on future Q ₁₀-related studies. We found that most Q ₁₀ values of each element were concentrated in a relatively narrow range despite a total data distribution over quite a wide range. For soil respiration, the median Q ₁₀ value was 2.74 and the center of the frequency distribution was between 2.0 and 2.5 with a percentage of 23%. Most of the data (>80%) were within the range from 1.0 to 4.0. The median Q ₁₀ value for root respiration was 2.40 and the center of the frequency distribution was from 2.5 to 3.0 with a percentage of 33%. Most of the results (>80%) ranged from 1.0 to 3.0. For stem respiration, the median Q ₁₀ value was 1.91 and the frequency distribution was concentrated between 1.5 and 2.0. Over 90% of the data ranged from 1.0 to 3.0. Obvious differences in Q ₁₀ value were found between different elements, stem < root < soil including root < soil excluding root. The differences between woody organisms of stems, roots, and soils excluding roots were statistically significant (p<0.05), indicating that heterotrophic respiration from microorganism activity may be more sensitive to global warming. The duration of the period with leaves slightly affects the temperature sensitivity of woody organisms since the Q ₁₀ values for root and stem of coniferous evergreen trees did not differ significantly from deciduous trees (p>0.10). CO₂ analytical methods (soda lime absorption method, IRGA (Infra-read gas analysis), and chromatograph analysis) and root separation methods (excised root and trenched box) slightly affected the Q ₁₀ values of soil and root respiration (p>0.10), but an in vitro measurement of stem respiration yielded a significantly higher Q ₁₀ value than an in vivo method (p<0.05). In general, although the Q ₁₀ values of non-photosynthetic organisms stayed within a relatively conservative range, considerable variation between and within elements were still detectable. Accordingly, attention should be paid to the quantitative estimation of total CO₂ efflux by Q ₁₀-related models. In future studies, the biochemical factors and the environmental and biological factors controlling respiration should be emphasized for precise estimation of total CO₂ efflux. The difficulty is how to clarify the underlying mechanism for fluctuations of Q ₁₀ values for one specific habitat and element (e.g. temperature acclimation or adaptation of Q ₁₀ values) and then allow the Q ₁₀ values to be more conservative for representation of temperature sensitivity in global warming processes. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(4) [译自:植物生态学报, 2005, 29 (4)]     

Seasonal changes of the mineral contents in the rumen of wild Yeso sika deer (Cervus nippon yesoensis)

The rumen contents were collected from 36 wild Yeso sika deer (Cervus nippon yesoensis) captured by deer culling or by hunting in the spring, summer, autumn and winter in Hokkaido, Japan. Botanical classification was conducted, and the contents of mineral (calcium (Ca), phosphorus (P), potassium (K), sodium (Na), iron (Fe), copper (Cu) and zinc (Zn)) were measured. The animals were captured around pastures or fallow field areas in the Kushiro area. The rumen contents consisted of grasses and Sasa sp. leaves regardless of the season. Leaves and bark were ingested in the spring, autumn and winter. The macro‐mineral contents in the rumen showed seasonal changes. In the summer, the Ca, K and P contents were high, and the Na content was low. There were no seasonal changes in the Fe content. The P, Na and Fe contents were higher than the animals' requirements. In a future survey, it is needed to determine the mineral contents of the food ingested by wild Yeso sika deer.