453 research outputs found
Male and female fertility in triploid grapes (Vitis complex) with special reference to the production of aneuploid plants
To produce aneuploid plants, the extent of male and female fertility in triploid grapes was studied using 187Ā tri-ploid hybrid plants obtained from 2x x 4x and 4x x 2x crosses. In the triploid plants, pollen germination rates examined on agar medium ranged from 0 to 5.88 % (average: 0.24Ā %). In 86 out of the 187 triploid plants none of the pollen grains germinated. In the 3x x 2x and 3x x 4x crosses, 10 triploid plants showing more than 1 % pollen germinationĀ ratesĀ producedĀ 191Ā seedsĀ fromĀ 7,692 pollinations and 109 seeds from 3,862 pollinations, respectively, whereas 10 triploid plants showing no pollen germination produced 98 seeds from 5,282 pollinations and 141Ā seeds from 5,293Ā pollinations, respectively. In the 3xĀ xĀ 2x and 3x x 4x crosses, the percentage of ovules developing into seeds varied in different triploid hybrid plants and ranged from 0.1Ā to 2.3 %. Of 8 aneuploid plants derived from the 3x x 2x and 3x x 4x crosses, one grew normally, three showed slow growth rates and 5 plants died after germination. These results suggest that in triploid grapes (1) there is no relationship between the degree of male fertility and that of female fertility, but the degree of the fertility is a triploid-plant-specific character, (2) female fertility is slightly higher than male fertility, and (3) male and female fertility is very low but aneuploid plants can be produced if triploid grapes with more than 0.3 % female fertility are used as seed parents
Fuzzy Fibers: Uncertainty in dMRI Tractography
Fiber tracking based on diffusion weighted Magnetic Resonance Imaging (dMRI)
allows for noninvasive reconstruction of fiber bundles in the human brain. In
this chapter, we discuss sources of error and uncertainty in this technique,
and review strategies that afford a more reliable interpretation of the
results. This includes methods for computing and rendering probabilistic
tractograms, which estimate precision in the face of measurement noise and
artifacts. However, we also address aspects that have received less attention
so far, such as model selection, partial voluming, and the impact of
parameters, both in preprocessing and in fiber tracking itself. We conclude by
giving impulses for future research
PosMed (Positional Medline): prioritizing genes with an artificial neural network comprising medical documents to accelerate positional cloning
PosMed (http://omicspace.riken.jp/) prioritizes candidate genes for positional cloning by employing our original database search engine GRASE, which uses an inferential process similar to an artificial neural network comprising documental neurons (or ādocumentronsā) that represent each document contained in databases such as MEDLINE and OMIM. Given a user-specified query, PosMed initially performs a full-text search of each documentron in the first-layer artificial neurons and then calculates the statistical significance of the connections between the hit documentrons and the second-layer artificial neurons representing each gene. When a chromosomal interval(s) is specified, PosMed explores the second-layer and third-layer artificial neurons representing genes within the chromosomal interval by evaluating the combined significance of the connections from the hit documentrons to the genes. PosMed is, therefore, a powerful tool that immediately ranks the candidate genes by connecting phenotypic keywords to the genes through connections representing not only geneāgene interactions but also other biological interactions (e.g. metaboliteāgene, mutant mouseāgene, drugāgene, diseaseāgene and proteināprotein interactions) and ortholog data. By utilizing orthologous connections, PosMed facilitates the ranking of human genes based on evidence found in other model species such as mouse. Currently, PosMed, an artificial superbrain that has learned a vast amount of biological knowledge ranging from genomes to phenomes (or āomic spaceā), supports the prioritization of positional candidate genes in humans, mouse, rat and Arabidopsis thaliana
Thin Film Growth and Device Fabrication of Iron-Based Superconductors
Iron-based superconductors have received much attention as a new family of
high-temperature superconductors owing to their unique properties and distinct
differences from cuprates and conventional superconductors. This paper reviews
progress in thin film research on iron-based superconductors since their
discovery for each of five material systems with an emphasis on growth,
physical properties, device fabrication, and relevant bulk material properties.Comment: To appear in J. Phys. Soc. Jp
Ablation of Mrds1/Ofcc1 Induces Hyper-Ī³-Glutamyl Transpeptidasemia without Abnormal Head Development and Schizophrenia-Relevant Behaviors in Mice
Mutations in the Opo gene result in eye malformation in medaka fish. The human ortholog of this gene, MRDS1/OFCC1, is a potentially causal gene for orofacial cleft, as well as a susceptibility gene for schizophrenia, a devastating mental illness. Based on this evidence, we hypothesized that this gene could perform crucial functions in the development of head and brain structures in vertebrates. To test this hypothesis, we created Mrds1/Ofcc1-null mice. Mice were examined thoroughly using an abnormality screening system referred to as āthe Japan Mouse Clinicā. No malformations of the head structure, eye or other parts of the body were apparent in these knockout mice. However, the mutant mice showed a marked increase in serum Ī³-glutamyl transpeptidase (GGT), a marker for liver damage, but no abnormalities in other liver-related measurements. We also performed a family-based association study on the gene in schizophrenia samples of Japanese origin. We found five single nucleotide polymorphisms (SNPs) located across the gene that showed significant transmission distortion, supporting a prior report of association in a Caucasian cohort. However, the knockout mice showed no behavioral phenotypes relevant to schizophrenia. In conclusion, disruption of the Mrds1/Ofcc1 gene elicits asymptomatic hyper-Ī³-glutamyl-transpeptidasemia in mice. However, there were no phenotypes to support a role for the gene in the development of eye and craniofacial structures in vertebrates. These results prompt further examination of the gene, including its putative contribution to hyper-Ī³-glutamyl transpeptidasemia and schizophrenia
Prevalence of sexual dimorphism in mammalian phenotypic traits
The role of sex in biomedical studies has often been overlooked, despite evidence of sexually dimorphic effects in some biological studies. Here, we used high-throughput phenotype data from 14,250 wildtype and 40,192 mutant mice (representing 2,186 knockout lines), analysed for up to 234 traits, and found a large proportion of mammalian traits both in wildtype and mutants are influenced by sex. This result has implications for interpreting disease phenotypes in animal models and humans
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