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Biomedical subjects

Teruo Yasunaga

Publications and source records attributed to Teruo Yasunaga.

7 recordsLinked to original sources
PubMed2004

Gene structure and evolution of testicular haploid germ cell-specific genes, Oxct2a and Oxct2b.

OXCT/SCOT is the rate-determining enzyme in ketolysis in mitochondria of many extrahepatic organs. Two testicular isoforms, Oxct2a and Oxct2b, are highly homologous and specifically expressed in haploid spermatids of the mouse. In this report, we analyzed the structure and evolution of Oxct2a and Oxct2b. Both Oxct2's are single-copy intronless genes, of which nucleotide sequences are conserved with Oxct, indicating that these genes are transposons generated from Oxct. A CpG island was found within both Oxct2's. Oxct2a and Oxct2b are located in the third introns of Bmp8a and Bmp8b, and they are positioned within a 240-kb region in a tail-to-tail orientation on chromosome 4. This structural feature was also conserved in a syntenic region of human 1p34.3. Structural similarity between mice and humans indicated that these two sets of genes were generated by a segmental gene duplication, which occurred before the primate-rodent split. Dot matrix and phylogenetic tree analyses demonstrated that multiple rounds of intrachromosomal gene conversion between the two loci occurred in each species independently.

Animals↗
PubMed2004

Application of revised version of neural independent component analysis to classification problems of confiscated methamphetamine.

Recently, profiling the chemical substances in illegally distributed drugs has been needed in order to reveal the drug channels. However, this kind of profiling is often difficult because such drugs contain various kinds of impurities and the quantity of these impurities changes. Due to these circumstances, several methods, including a slightly revised ICA (Independent Component Analysis) by a Hebbian learning artificial neural network, were applied for profiling illegally distributed methamphetamine. Eventually, better classification results with the ICA than with other methods were obtained. These results show that ICA could make it easier to profile illegally distributed methamphetamine.

Algorithms↗
PubMed2003

Genome sequence of Vibrio parahaemolyticus: a pathogenic mechanism distinct from that of V cholerae.

BACKGROUND: Vibrio parahaemolyticus, a gram-negative marine bacterium, is a worldwide cause of food-borne gastroenteritis. V parahaemolyticus strains of a few specific serotypes, probably derived from a common clonal ancestor, have lately caused a pandemic of gastroenteritis. The organism is phylogenetically close to V cholerae, the causative agent of cholera. METHODS: The whole genome sequence of a clinical V parahaemolyticus strain RIMD2210633 was established by shotgun sequencing. The coding sequences were identified by use of Gambler and Glimmer programs. Comparative analysis with the V cholerae genome was undertaken with MUMmer. FINDINGS: The genome consisted of two circular chromosomes of 3288558 bp and 1877212 bp; it contained 4832 genes. Comparison of the V parahaemolyticus genome with that of V cholerae showed many rearrangements within and between the two chromosomes. Genes for the type III secretion system (TTSS) were identified in the genome of V parahaemolyticus; V cholerae does not have these genes. INTERPRETATION: The TTSS is a central virulence factor of diarrhoea-causing bacteria such as shigella, salmonella, and enteropathogenic Escherichia coli, which cause gastroenteritis by invading or intimately interacting with intestinal epithelial cells. Our results suggest that V parahaemolyticus and V cholerae use distinct mechanisms to establish infection. This finding explains clinical features of V parahaemolyticus infections, which commonly include inflammatory diarrhoea and in some cases systemic manifestations such as septicaemia, distinct from those of V cholerae infections, which are generally associated with non-inflammatory diarrhoea.

Cholera↗
PubMed2003

Genome sequence of an M3 strain of Streptococcus pyogenes reveals a large-scale genomic rearrangement in invasive strains and new insights into phage evolution.

Group Astreptococcus (GAS) is a gram-positive bacterial pathogen that causes various suppurative infections and nonsuppurative sequelae. Since the late 1980s, streptococcal toxic-shock like syndrome (STSS) and severe invasive GAS infections have been reported globally. Here we sequenced the genome of serotype M3 strain SSI-1, isolated from an STSS patient in Japan, and compared it with those of other GAS strains. The SSI-1 genome is composed of 1,884,275 bp, and 1.7 Mb of the sequence is highly conserved relative to strain SF370 (serotype M1) and MGAS8232 (serotype M18), and almost completely conserved relative to strain MGAS315 (serotype M3). However, a large genomic rearrangement has been shown to occur across the replication axis between the homologous rrn-comX1 regions and between two prophage-coding regions across the replication axis. Atotal of 1 Mb of chromosomal DNA is inverted across the replication axis. Interestingly, the recombinations between the prophage regions are within the phage genes, and the genes encoding superantigens and mitogenic factors are interchanged between two prophages. This genomic rearrangement occurs in 65% of clinical isolates (64/94) collected after 1990, whereas it is found in only 25% of clinical isolates (7/28) collected before 1985. These observations indicate that streptococcal phages represent important plasticity regions in the GAS chromosome where recombination between homologous phage genes can occur and result not only in new phage derivatives, but also in large chromosomal rearrangements.

Attachment Sites, Microbiological↗
PubMed2002

Identification of PGC7, a new gene expressed specifically in preimplantation embryos and germ cells.

The gene expression patterns of primordial germ cells (PGCs) and embryonic stem cells were analyzed by a modified serial analysis of gene expression. During the process, we cloned a novel gene, PGC7, which was preferentially expressed in PGCs. Immunohistochemical analysis revealed that PGC7 was specifically expressed in early pre-implantation embryos, PGCs and oocytes. These results suggest that PGC7 might play an important role in the development of PGCs and oocytes.

Amino Acid Sequence↗
PubMed2002

Study of transcripts from AC010088, a 199,485 bp fragment of the human Y chromosome located in the azoospermia factor region c.

Deletions on the long arm of the human Y chromosome are associated with male infertility. In this work, we studied transcripts of a 199,485 bp long fragment of the Yq11 region (GenBank accession number, AC010088) located in the AZFc (azoospermia factor region c), and characterized their gene structures. After masking repetitive elements, we searched human mRNA Refseqs (reference sequences), a dbEST (database of expressed sequence tags) and a non-redundant nucleic acid database for the mRNAs and ESTs corresponding to the AC010088 using the BLAST programs at the NCBI (National Center for Biotechnology Information) site. Our findings are summarized as follows: i) BPY2 (testis basic protein on Y, 2), DAZ1 (deleted in azoospermia 1), TTY4 (testis transcript Y 4) mRNAs and 23 ESTs were found; ii) Eighteen of 23 ESTs were transcripts of the DAZ gene(s), one EST was a transcript of TTY4 gene, and the remaining 4 probably corresponded to 4 different pseudogenes; iii) DAZ gene(s) were expressed not only in testis, but also in lung carcinoma cells, stomach and Ewing's sarcoma cells; iv) beta-satellite clusters were present around and within the BPY2 and TTY4 gene region; v) In this study, TTY4, BPY2 and DAZ1 genes were mapped precisely to the AC010088 region.

Chromosome Mapping↗