Method to quantify root border cells in sandy soil

Root border cells are cells that detach from the growing root cap, and serve both physical and biological roles in the rhizosphere. Most work on border cells has been confined to agar, or hydroponic culture, because of the difficulty in separating them from soil particles. We present a new method to separate the root border cells from soil, and quantify border cell numbers in non-sterile sandy loam soil at contrasting matric potentials (−20 and −300 kPa). Recovery rates of 90±1% were achieved using a combination of surfactants, sonication, and centrifugation. Root border cell numbers in the dry soil (1.4×10³ after 24 h) were significantly decreased as compared with those in the wetter soil (1.7×10³ after 24 h). Possible reasons for the decreased release of border cells are discussed.     

Annual Changes in Some Physiological Properties of Cryptomeria Japonica Leaves from Kanto, Japan

C. japonica leaves were sampled monthly in a heavily damaged area (a-I: Saitama), a slightly damaged area (a-II: plains in Ibaraki), and a healthy area (a-III: mountainous areas in Ibaraki) in Kanto. The leaves were analyzed for apparent cuticular transpiration rates, amounts of epicuticular wax, and contact angles. Sb in aerosols deposited on the leaves was also analyzed. The transpiration rates and the increase in transpiration with leaf aging were higher in a-I than in a-II and a-III. Erosion rates of the wax were higher in a-I and a-II than in a-III. The decrease of contact angles with aging tended to be higher in a-I and a-II than in a-III. Rates of aerosol-Sb deposition on the leaves were in the order a-I ? a-II > a-III. The transpiration rates correlated with the values obtained from a linear binomial function that included the amounts of wax and aerosol-Sb as variables (r = 0.855, P < 0.01). In a-I, the large quantity of aerosols on the leaves (and probably gaseous air pollutants) may have increased the transpiration rates by ca. 50% owing to erosion of the wax and stomatal malfunction, placing C. japonica under chronic water stress.     

Topographic relationship between senile plaques and cerebrovascular amyloidosis in the brain of aged dogs.

The distributions of senile plaques (SP) and cerebrovascular amyloidosis (CA) were studied by employing thioflavin S and modified Bielschowsky stains, and beta-protein immunohistochemistry on serial sections of the brains of aged dogs older than 10 years. Mature and perivascular plaques, both of which contained compact amyloid deposits, always showed a close topographic relationship to CA. In contrast, the majority of diffuse plaques showed no topographic relationship to CA. Cell bodies of neurons and/or glia were almost always involved in the diffuse plaques. In addition, beta-protein immunohistochemistry demonstrated amyloid deposits on the periphery of occasional neurons. These findings suggest that different mechanisms may be involved in the development of the different subtypes of SP in the brains of aged dogs.     

High incidence of rickettsiosis correlated to prevalence of Rickettsia japonica among Haemaphysalis longicornis tick

Endemic spotted fever group rickettsiosis was reported in Shimane Prefecture, Japan. From an analysis of 14 clinical cases found in the endemic area, the infectious agent of spotted fever group rickettsiosis was identified as Rickettsia japonica. In this study, we also found that Rickettsia japonica was highly infected with the vector tick, Haemaphysalis longicornis, in the endemic area. These findings suggest that the high incidence of rickettsiosis in Shimane Prefecture can be explained by the high prevalence of Rickettsia japonica among Haemaphysalis longicornis ticks.     

Novel genomic and EST-derived SSR markers in Japanese chestnuts

A total of 366 novel simple sequence repeat (SSR) markers were developed in Japanese chestnut (Castanea crenata), comprising 220 genomic SSRs derived from enriched genomic libraries and 146 expressed sequence tag (EST)–SSRs obtained from large-scale EST sequencing analysis. Thirty accessions, comprising Japanese, Chinese (C. mollissima), European (Castanea sativa), and American chestnuts (Castanea dentata), were used for evaluation of SSR polymorphism and transferability across species. The EST–SSRs showed less polymorphism than the genomic SSRs and were more transferable. The mean observed heterozygosity (H_O) and the mean expected heterozygosity (H_E) of genomic SSRs in the Japanese chestnuts were 0.63 and 0.68, respectively; those of EST-SSRs were each 0.47. Although about 80% of the genomic SSRs were amplified in all 4 species, more than 95% of the EST–SSRs were transferable across all 4 species. The many novel SSRs developed in this study will be applicable for the construction of genetic linkage maps, QTL analysis of phenotypic traits, high-throughput genotyping of marker-assisted selection, and association genetics.     

In vitro and in vivo consequences of VLA-2 expression on rhabdomyosarcoma cells

Cloned integrin alpha 2 subunit complementary DNA was expressed on human rhabdomyosarcoma (RD) cells to give a functional VLA-2 (alpha 2 beta 1) adhesion receptor. The VLA-2-positive RDA2 cells not only showed increased adhesion to collagen and laminin in vitro, but also formed substantially more metastatic tumor colonies in nude mice after either intravenous or subcutaneous injection. These results show that a specific adhesion receptor (VLA-2) can markedly enhance both experimental and spontaneous metastasis. In contrast to the metastasis results, there was no difference in either the in vitro growth rate or apparent in vivo tumorigenicity of RD and RDA2 cells.     

Variations in cryptic assemblages in coral-rubble interstices at a reef slope in Ishigaki Island,Japan

The interstices of coral rubble provide a good refuge for cryptic small crustaceans and molluscs, which are important prey items for reef fishes. In this study, we focused on the assemblage composition of cryptic mobile species along the depth gradient at an outer reef slope. Traps with coral rubble (22 × 18 × 6 cm) were set at three sites at different depths, and mobile animals that colonized the traps were sorted. In total, 117 species of larger animals (mainly Decapoda and Gastropoda) were recorded: 71 species at the 3 m point, 53 species at the 11 m point, and 37 species at the 22 m point. On average, 260.3 individuals were captured in the traps at 3 m, while 95.3 and 57.8 individuals were captured at 11 and 22 m, respectively. MDS ordination showed that assemblage composition differed among the three sites. The most abundant species at the 3 m was the galathean crab Galathea mauritiana, followed by the gastropod Diala albugo. At 11 and 22 m, the galathean crab Sadayoshia edwardsii was most abundant. Thus, at the reef slope, the benthic assemblage was most diverse at the shallow site, and specific communities occurred at the three sites.     

Direct genotyping of single pollen grains of a self-compatible mutant of Japanese pear (Pyrus pyrifolia) revealed inheritance of a duplicated chromosomal segment containing a second S-haplotype

Radiation mutant 415-1, which is the first known diploid pollen-part self-compatible mutant of pears (Pyrus spp.), has a decreased ability to produce pollen. To determine whether the self-compatibility trait is associated with this defect, we directly analyzed the genotypes of individual pollen grains by using polymerase chain reaction amplification of DNA from single pollen grains. We isolated single pollen grains from 415-1 and succeeded in genotyping the S-RNase gene and three simple sequence repeat (SSR) markers in linkage group 17. Out of 173 individual pollen grains, 28 (16 %) were S-heteroallelic. These pollen grains had two alleles each of the S-RNase gene and of two linked SSR loci, all on a duplicated chromosomal segment, but only one allele of a non-duplicated locus farther away on the same chromosome. The segregation ratio of each marker in the pollen from 415-1 was approximately the same as that observed in outcross progeny. This suggests that the decrease in frequency of pollen with the duplicated S-haplotype occurred during meiosis or pollen formation, but that the probability of fertilization by S-heteroallelic pollen is equal to that of single-allelic pollen. However, the partial sterility in 415-1 can also be attributed to one or more unidentified lethal mutations unlinked to the duplicated segment encompassing the S-haplotype. Single-pollen genotyping can be used in a variety of applications in genetic research because in cases where all pollen genotypes are proportionately represented in the progeny, segregation ratios can be obtained without producing the next generation.     

Histopathological, immunohistochemical and ultrastructural studies of a renal mesenchymal tumor in a young beagle dog

A 15-month-old male beagle dog used in a toxicity study had a primary renal mesenchymal tumor. Macroscopically, the tumor was a gray-white mass which was found in the right kidney, and extended from the capsule to a position slightly compressing the medulla. Microscopically, most of the tumor cells showed a myxoid pattern, in which the matrix was positive for alcian blue staining. In the other parts of the tumor, a fascicular and wavy pattern was observed, and the matrix was full of collagen fibrils. Immunohistochemically, tumor cells were positive for vimentin and fibronectin, and negative for cytokeratin, desmin, α-smooth muscle actin, Von Willebrand factor, cyclooxigenase-2 and myelin basic protein. As a result, we diagnosed this case to be a renal mesenchymal tumor. Based on the microscopic findings, interstitial characteristics and immunohistochemical features, the present case was classified as a congenital mesoblastic tumor.