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.     

Comparisons of age,growth, and maturity between male and female,and diploid and triploid individuals in Carassius auratus from Okinawa‐jima Island,Japan

• 1. Carassius auratus, a primary freshwater fish with bisexual diploid and unisexual gynogenetic triploid lineages, is distributed widely in and around the Eurasian continent and is especially common in East Asia. East Asian C. auratus diverged genetically to form local endemic populations in different regions, and those distributed in the Ryukyu Archipelago form a local endemic population that can be regarded as an evolutionarily significant unit because of its high phylogenetic independence and evolutionary distinctiveness. Although the evolutionary uniqueness of this population should be conserved, its distribution area and population size are decreasing rapidly, and some island populations are currently considered endangered or already extinct.
• 2. To develop effective conservation measures to stop the current decline of Ryukyuan C. auratus, ecological data need to be collected. In this study, life history data for a C. auratus population distributed in the Hiji River system were collected by estimating age, growth, and spawning season.
• 3. The spawning season of C. auratus in the Hiji River extended from March to September, peaking during March–May. Females became sexually mature in their second year, but males reached maturity and were able to spawn as early as in the late spawning season of their year of hatching. Once having reached sexual maturity, males probably continuously stay ripe throughout their life.
• 4. Sagittal otoliths of C. auratus proved to be useful ageing structures because one annual increment is formed on the sagittal otolith before the spawning season in each year. The oldest fish observed were a 10‐year‐old female and an 11‐year‐old male. Females showed faster somatic growth and higher final standard length than males, and a sexual size dimorphism was observed.
• 5. The standard length at each age class did not differ between diploid and triploid C. auratus, suggesting that triploid growth rates were almost equal to those of diploids. Copyright © 2009 John Wiley & Sons, Ltd.

     

Establishment of an IL-2-dependent bovine T cell line and an assay of lymphocyte response inhibition in leukemic bovine serum.

The mechanism of immunosuppression induced by leukemic bovine serum was investigated with respect to lymphokine reactions using an interleukin 2 (IL-2)-dependent bovine T cell line generated from bovine peripheral blood lymphocytes (PBLs). The suppression of concanavalin A (con A)-induced PBL blastogenesis was observed at a high rate in leukemic cattle sera. The growth of IL-2-dependent bovine T cells and IL-2 production from con A-induced bovine PBLs were also inhibited by these sera, and particularly, the latter was correlated significantly to the degree of lymphocyte blastogenesis by the mitogen. Therefore, the lesser sensitivity of lymphocytes to IL-2 and the reduced IL-2 production by activated lymphocytes seem to play a role in suppressing the lymphocyte reaction.     

Databases for technical aspects of immunohistochemistry: 2021 update

With the aim of sharing information about the technical aspects of immunohistochemistry (IHC) and facilitating the selection of suitable antibodies for histopathological examination, this technical report describes the results of a questionnaire distributed during the period of 2018 to 2019 among members of the Conference on Experimental Animal Histopathology. Additionally, it describes the immunological properties and supplier details (clone, supplier, catalog number, species reactivity, etc.) as well as the IHC staining conditions (fixing solution, fixing time, embedding, antigen retrieval method, antibody dilution, incubation time, incubation temperature, positive control tissue, blocking condition, secondary antibody information, etc.) for a total of 509 primary antibodies (comprising 220 different types). These survey results were an update on the contents reported by CEAH in 2017.     

Comparison of polymerase chain reaction-restriction fragment length polymorphism assay and enzyme assay for diagnosis of G(M1)-gangliosidosis in Shiba dogs.

In the present study, diagnostic methods for canine G(M1)-gangliosidosis were examined by comparing a DNA mutation assay with an enzyme assay. Sixty-two Shiba dogs of a pedigree with G(M1)-gangliosidosis were differentiated into 3 genotypes, i.e., normal, heterozygous, and homozygous affected dogs, using a DNA mutation assay, which consists of polymerase chain reaction amplification and the determination of restriction fragment length polymorphisms. The beta-galactosidase activity in leukocytes, umbilical cords, and plasma was measured using 4-methylumbelliferyl beta-D-galactoside and p-nitrophenyl beta-D-galactoside as artificial substrates and compared among the 3 genotypes. The results showed that it was possible to identify homozygous dogs with the enzyme assay using leukocytes and umbilical cords. When using leukocytes, heterozygous carriers could be differentiated from normal dogs in many cases. However, the use of the DNA mutation assay is essential for a complete determination of heterozygous carriers because of the overlap in the distribution of enzyme activity between these 2 groups. When umbilical cords were used, heterozygous carriers could not be differentiated from normal dogs because of no significant difference in enzyme activity between these 2 groups. The beta-galactosidase activity in plasma was not applicable to the diagnosis and genotyping of G(M1)-gangliosidosis in Shiba dogs.     

Atmospheric Concentrations of Sulfur Dioxide and Nitrogen Dioxide in China and Korea Measured by Using the Improved Passive Sampling Method

The results of ambient sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) concentrations measured in ten cities of China and Korea by the improved passive samplers are reported. The property of this sampler is the utilization for the long-term exposure to the high level of SO₂ and NO₂. In this method, the conversion coefficients from the analytical data to the ambient concentrations were obtained from the comparison with the direct concentrations through the automatic analyzers for SO₂ and for NO₂, respectively. The interesting monthly variations were observed in the ambient SO₂ and NO₂ concentrations measured by this passive sampler method, which seems to give important information to the formation of acid rain in these countries.     

Antibody titers in cattle clinically and subclinically infected with bovine leukemia virus

Antibody titers to protein (p) and glycoprotein (gp) antigens of bovine leukemia virus were studied by the immunodiffusion test in two groups of cattle. One group showed evidence of enzootic bovine leukosis (BL+ cattle), whilst the second group, possessing antibodies to gp antigen, were adjudged as subclinical cases (BL?). All 165 BL? and 97% (108/111) BL+ cattle possessed antibodies to gp antigen but those to p antigen were evident in only 67% BL? cattle in contrast to 89% in BL+ cattle. Mean antibody titers to both antigens were statistically higher in BL+ cattle.