Biomedical subjects
Publications and source records attributed to Masao Watanabe.
Serial evaluation of diffusion tensor brain fiber tracking was performed in a 27-year-old female patient with diffuse axonal injury after a traffic accident. Although the result of brain fiber tracking was not necessarily parallel to her clinical symptoms, it may have predicted the neurologic prognosis.
An interspecific hybrid between leek ( Allium ampeloprasum L.) and garlic ( Allium sativum L.) was produced by hybridization using a fertile garlic clone as a pollen donor and an ovary culture. The hybridity was confirmed by chromosome observation (2n = 3 x = 24) and randomly amplified polymorphic DNA (RAPD) analysis. The interspecific hybrid showed a vigorous growth habit, and its foliage was larger than that of the parental species. The bulb of the interspecific hybrid was heavier than that of the parents, containing an intermediate number of cloves. The hybrid could be propagated vegetatively by planting cloves. The odor compounds of garlic, which leek did not have, were detected in the volatiles of the hybrid with a certain concentration. The results of the study suggest the possibility of direct use of an interspecific hybrid between A. ampeloprasum and A. sativum as a new crop.
RATIONALE AND OBJECTIVES: A novel method to correct flow data from magnetic resonance phase contrast (MR-PC) angiography, based on combining computational fluid dynamics and segmentation in a level set framework, was developed and tested in this study. MATERIALS AND METHODS: The MR-PC velocity data was used in a partial differential equation-based level set method for vessel segmentation. The results were supplied as the quantitative description of the vessel wall to the flow field solver using computational fluid dynamics, based on the level set method, to obtain a physically meaningful flow. The most significant characteristic of our novel approach is that it requires light computational loads, especially insofar as it avoids generation of complex computational grid system. The integration of segmentation and computational fluid dynamics in a level set framework is shown to be both robust and economic, and yet yields a physically correct velocity field and optimal vessel geometry. RESULTS: The application to the flow field in a straight tube with circular cross section of constant radius demonstrated the validity of out new approach, especially the treatment of the velocity boundary conditions on the solid wall. Simulation of the velocity field in both common carotid artery and bifurcation of basilar and vertebral arteries, based on clinical MR-PC data, provided with smooth and stable results. CONCLUSION: Applying this procedure to both synthetic and clinical data, significant improvement of the blood velocity field, such as a smooth velocity distribution aligned along the vessels and removal of burst or error vectors, could be observed. This procedure also offers possibilities for improved vessel segmentation.
Self-incompatibility (SI) prevents self-fertilization by rejecting pollen from plants with the same S phenotype. The Brassica SI system is controlled sporophytically by multiple alleles at the single locus, S, and dominance relationships among S haplotypes are observed in both stigma and pollen. We have identified previously five different class-II S haplotypes in Brassica campestris. Here, we performed test-crosses between S heterozygotes and their respective parental S homozygotes for four of these class-II S haplotypes, and observed a linear dominance relationship on the pollen side. To determine how this relationship is controlled, we performed RNA gel blot analyses for six S heterozygotes and their respective parental S homozygotes using the corresponding SP11 clone as a probe. In all six S heterozygotes, SP11 derived from a dominant haplotype was predominantly expressed, and SP11 derived from a recessive haplotype was repressed. Thus, the linear dominance relationship of the SI phenotype on the pollen side is regulated by the expression of SP11.
To gain some insights into the structure of the S-locus and the mechanisms that have kept its diversity, a 75-kb genomic fragment containing the self-incompatibility (S) locus region was isolated from the S12-haplotype of Brassica rapa and compared with those of other S-haplotypes. The region around the S determinant genes was highly polymorphic and filled with S-haplotype-specific intergenic sequences. The diverse genomic structure must contribute to the suppression of recombination at the S-locus.
To understand the molecular mechanisms intrinsic to reproductive organ development a cDNA microarray, fabricated from flower bud cDNA clones, was used to isolate genes, which are specifically expressed during the development of the anther and pistil in Lotus japonicus. Cluster analysis of the microarray data revealed 21 and 111 independent cDNA groups, which were specifically expressed in immature and mature anthers, respectively. RT-PCR was performed to provide a direct assessment of the accuracy and reproducibility of our approach. Confirmation of our results suggests that cDNA microarray technology is an effective tool for identification of novel reproductive organ-specific genes.
SRK is a plant receptor kinase involved in the self-incompatibility system of Brassica species. During a cDNA screening for the phosphoproteins from a stigma expression library, a clone encoding the nucleoside diphosphate kinase III (Bc-NDPK III) was obtained. After in vitro phosphorylation assays with recombinant proteins, Bc-NDPK III contained mostly phosphoserine. By contrast, the kinase domain of SRK contained phosphoserine and phosphothreonine, both of which were significantly increased by the addition of Bc-NDPK III in the presence of an SRK inhibitor KN-62. The result suggested the possible involvement of Bc-NDPK III in the signal transduction pathway through SRK.
Self-incompatibility (SI) in Brassica is controlled sporophytically by the multiallelic S-locus. The SI phenotype of pollen in an S-heterozygote is determined by the relationship between the two S-haplotypes it carries, and dominant/recessive relationships often are observed between the two S-haplotypes. The S-locus protein 11 (SP11, also known as the S-locus cysteine-rich protein) gene has been cloned from many pollen-dominant S-haplotypes (class I) and shown to encode the pollen S-determinant. However, SP11 from pollen-recessive S-haplotypes (class II) has never been identified by homology-based cloning strategies, and how the dominant/recessive interactions between the two classes occur was not known. We report here the identification and molecular characterization of SP11s from six class II S-haplotypes of B. rapa and B. oleracea. Phylogenetic analysis revealed that the class II SP11s form a distinct group separated from class I SP11s. The promoter sequences and expression patterns of SP11s also were different between the two classes. The mRNA of class II SP11, which was detected predominantly in the anther tapetum in homozygotes, was not detected in the heterozygotes of class I and class II S-haplotypes, suggesting that the dominant/recessive relationships of pollen are regulated at the mRNA level of SP11s.
Lotus japonicus has received increased attention as a potential model legume plant. In order to study gene expression in reproductive organs and to identify genes that play a crucial function in sexual reproduction, we constructed a cDNA library from immature flower buds containing anthers at the stage of developing tapetum cells in L. japonicus, and characterized 919 expressed sequence tags (ESTs) randomly selected from a cDNA library of the immature flower buds. The 919 ESTs analyzed were clustered into 821 non-redundant EST groups. As a result of a database search, 436 groups (53%) out of the 821 groups showed sequence similarity to genes registered in the public database. Out of these 436 groups, 109 groups showed similarity to genes encoding hypothetical proteins whose function had not yet been estimated. Three hundred eighty five groups (47%) showed no significant homology to known sequences and were classified as novel sequences. A comparison of 821 non-redundant EST sequences and EST sequences derived from the whole plant L. japonicus revealed that 474 EST sequences derived from immature flower buds were not found in the EST sequences of the whole plant. In order to confirm the expression pattern of potential reproductive-organ specific EST clones, nine clones, which were not matched to ESTs derived from the whole plant, were selected, and RT-PCR analysis was performed on these clones. As a result of RT-PCR, we found two novel anther specific clones. One clone was homologous to a gene encoding human cleft lip and palate associated transmembrane protein (CLPTM1) like protein, and the other clone did not show a significant similarity to any genes deposited in the public database. These results indicate that ESTs analyzed here represent a valuable resource for finding reproductive-organ specific genes in Lotus japonicus.