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Biomedical subjects

E Takahashi

Publications and source records attributed to E Takahashi.

At least 19 recordsLinked to original sources
PubMed1995

Expression of the human cGMP-dependent protein kinase II gene is lost upon introduction of SV40 T antigen or immortalization in human cells.

We have cloned a human cGMP-dependent protein kinase type II cDNA to examine its gene expression in terms of cellular senescence and/or immortalization. The genetic locus was mapped to band 4q21 by FISH. Northern blot analysis revealed that expression of the type II gene was markedly decreased or lost in mortal or immortal human fibroblasts producing SV40 T antigen. Also in various immortalized cell lines tested, the gene was not expressed. In normal diploid fibroblasts, the gene was constitutively expressed during cell-cycle and population doubling levels (PDLs).

Amino Acid Sequence↗
PubMed1995

Cloning, mapping and expression of PEBP2 alpha C, a third gene encoding the mammalian Runt domain.

PEBP2/CBF is a heterodimeric transcription factor composed of alpha and beta subunits. Previously, we reported two distinct mouse genes, PEBP2 alpha A and PEBP2 alpha B, which encode the alpha subunit. PEBP2 alpha B is the homologue of human AML1, encoding the acute myeloid leukemia 1 protein. AML1 and human PEBP2/CBF beta were detected independently at the breakpoints of two characteristic chromosome translocations observed frequently in two subtypes of acute myeloid leukemia. The PEBP2 alpha proteins contain a 128-amino-acid (aa) region highly homologous to the Drosophila melanogaster segmentation gene runt. The evolutionarily conserved region, named the Runt domain, harbors DNA-binding and heterodimerizing activities. In this study, we identified the third Runt-domain-encoding gene, PEBP2 alpha C, which maps to 1p36.11-p36.13 in the human chromosome and encodes a 415-aa protein. PEBP2 alpha C forms a heterodimer with PEBP2 beta, binds to the PEBP2 site and transactivates transcription, similar to PEBP2 alpha A and PEBP2 alpha B.

Amino Acid Sequence↗
PubMed1995

The human gene encoding the largest subunit of RNA polymerase II.

The nucleotide sequence of a large portion of the human RNA polymerase II large subunit (RpII LS)-encoding gene and its whole gene structure were determined. The RpIILS gene consists of 29 exons. The sequence of the 5' flanking region is highly conserved as compared with that of the mouse RpIILS and contains several SP1-binding sites, a CCAAT sequence and a sequence homologous to a heat-shock element. In addition, several inverted repeats and palindrome sequences were involved in the 5' upstream region. Those suggest that the 5' flanking domain of RpIILS would be highly structured which may be responsible for transcriptional regulation.

Amino Acid Sequence↗
PubMed1995

Human alpha-tocopherol transfer protein: cDNA cloning, expression and chromosomal localization.

alpha-Tocopherol transfer protein (alpha TTP), which specifically binds this vitamin and enhances its transfer between separate membranes, was previously isolated from rat liver cytosol. In the current study we demonstrated the presence of alpha TTP in human liver by isolating its cDNA from a human liver cDNA library. The cDNA for human alpha TTP predicts 278 amino acids with a calculated molecular mass of 31,749, and the sequence exhibits 94% similarity with rat alpha TTP at the amino acid level. The recombinant human alpha TTP expressed in Escherichia coli exhibits both alpha-tocopherol transfer activity in an in vitro assay and cross-reactivity to the anti-(rat alpha TTP) monoclonal antibody. Northern blot analysis revealed that human alpha TTP is expressed in the liver like rat alpha TTP. The human and rat alpha TTPs show structural similarity with other apparently unrelated lipid-binding/transfer proteins, i.e. retinaldehyde-binding protein present in retina, and yeast SEC14 protein, which possesses phosphatidylinositol/phosphatidylcholine transfer activity. Both Southern-blot hybridization of human-hamster somatic cell hybrid lines and fluorescence in situ hybridization revealed a single alpha TTP gene corresponding to the 8q13.1-13.3 region of chromosome 8, which is identical to the locus of a recently described clinical disorder, ataxia with selective vitamin E deficiency (AVED). The relationship between alpha TTP and AVED will be discussed.

Amino Acid Sequence↗
PubMed1995

Transplantation of reproductive organs.

A historical review of the literature concerning replantation and transplantation of reproductive organs has included studies from this laboratory, using rats, over the past 25 years. From the basic observation of ischemic and traumatic injury due to the transplantation, syngeneic testicle transplants, resulting in a partner's impregnation and histological restoration of the testicles, led to human testicular transplantation. As to the ovarian transplants, granulosa-theca cell tumors may transform into malignancies if followed for a prolonged period as intrasplenic ovaries, and high doses (15 to 20 mg/kg b.w.) of azathioprine can produce such malignant tumors in a shorter period. By caval-portal shunt, ovarian hormones enter directly into the portal blood stream and no typical granulosa-theca cell tumors were produced, owing to the fact that the liver cannot degrade all the hormones secreted by both ovaries. While en-bloc vagino-utero-ovarian transplantation in the rat is possible, no impregnation has been yet achieved. Finally, it is hypothesized that those who have acquired microsurgical techniques and have a full understanding of the anatomy of the reproductive system will not only be able to perform replantation of the penis, but also will be capable of allogeneic transplantation of genital organs, whether ethically approved or not, and sooner than one may think. In such cases a penile part may be obtained at a sex-change surgery or from a cadaveric donor, similar to other vital organ transplantation practices.

Animals↗
PubMed1995

Cytotoxin detection in Campylobacter jejuni strains of human and animal origin with three tissue culture assay systems.

Cytotoxin (CTX) production in 34 human and 22 animal strains of Campylobacter jejuni isolated in Japan and other countries was studied by three assay systems described previously. Furthermore, cholera-like enterotoxin production by these strains was tested by reversed passive latex agglutination (RPLA). CTX titres in the fetal calf serum (FCS) and newborn calf serum (NCS) assays were relatively lower, with a maximum of 4 and 8, respectively, than the maximum of 128 for the serum-free culture (SFC) assay. CTX detection rates were 62, 85 and 100% in human isolates and 64, 77 and 100% in animal isolates for the FCS, NCS and SFC assay systems, respectively. There was no significant difference in the detection rate of CTX between human and animal isolates, or between human isolates from Japan and other countries. With the three assay systems, the strains were divided into four groups from the pattern of CTX detection; 54% of strains gave positive results in all three assay systems, and 9% of them were positive in the SFC assay only. Morphological changes on CHO cells showed distended instead of rounded cells with eight of 21 strains negative in the FCS assay. Cholera-like enterotoxin was not detected in the culture filtrate of any of the strains when tested by RPLA. These results indicate that cytotoxin production by C. jejuni is complex as compared with that of other enteric pathogens.

Animals↗
PubMed1995

The antimicrobial activity of hexapeptides derived from synthetic combinatorial libraries.

A series of peptides identified through the use of synthetic hexapeptide combinatorial libraries (represented by the formula Ac-RRWWCO-NH2) were examined for their antimicrobial activity against five different micro-organisms. Their toxicity was also evaluated in an in vitro haemolytic assay. The peptides showed activity against the five micro-organisms, although higher activities were found against Gram-positive bacteria. Both growth inhibition and cell viability assays were carried out to demonstrate the bactericidal activities of these peptides against two of the micro-organisms tested. The dimeric cystine forms of these peptides were shown to have biological activities identical to the monomeric forms.

Amino Acid Sequence↗
PubMed1995

Detection of alpha- and beta-hemolytic-like activity from Campylobacter jejuni.

Alpha-hemolytic-like activity from Campylobacter jejuni was clearly apparent when the medium pH ranged from 6.0 to 6.5, but the hemolytic zones disappeared when the pH of the medium increased. Beta-hemolytic-like activity just beneath the bacterial growth appeared after prolonged incubation. The hemolytic activity was not influenced by the species of blood.

Animals↗
PubMed1995

Visualization of oxygen level inside a single cardiac myocyte.

The present paper describes theoretical and experimental bases for quantitation of the oxygen level inside a single isolated ventricular rat myocyte. We applied three-wavelength microspectrophotometry to a single cardiomyocyte, where the sensitivity of the spectrophotometry was augmented by a digital image processing technique known as video-enhanced microscopy. Oxygen-dependent changes in light absorption of the intracellular pigments were detected and represented with the use of a newly defined variable, Z, where one pixel of the reconstructed cell image corresponded to 0.2 microns. Theoretically, Z is a single-valued function of the fractional oxygen saturation of the intracellular pigment. We demonstrated in quiescent cardiomyocytes that Z changed according to extracellular PO2, where the relationship was sigmoidal with the extracellular PO2 for a half-maximal Z of 3.2 Torr. In the aerobic cell, conversion of cytochromes to the reduced forms by NaCN did not affect Z value. Therefore, we conclude that Z mainly represents the fractional oxygen saturation of myoglobin, thus reporting cytosolic PO2. We also demonstrated that for extracellular PO2 of 1.3 Torr, abolition of mitochondrial oxygen consumption by NaCN significantly elevated the intracellular oxygen level, suggesting existence of oxygen pressure gradients in a quiescent single cardiomyocyte that were proportional to oxygen flux.

Animals↗
PubMed1995

A high-resolution cytogenetic map of human chromosome 2: localization of 434 cosmid markers by direct R-banding fluorescence in situ hybridization.

We have constructed a high-resolution cytogenetic map of human chromosome 2 with 434 newly isolated cosmid markers by means of direct R-banding fluorescence in situ hybridization. Two markers were mapped to the centromeric region, 173 to the short arm, and 259 to the long arm. The clones were evenly distributed along the entire chromosome, although a tendency toward clustering in R-positive bands was observed. The mapped cosmids provide useful landmarks for construction of a contig map and for positional cloning of cancer-associated genes, as well as genes responsible for hereditary diseases.

Animals↗
PubMed1995

Isolation and mapping of the human beta-signal sequence receptor gene (SSR2).

We have isolated a human cDNA clone homologous to the canine beta-signal sequence receptor gene, which codes for an endoplasmic reticulum (ER) membrane protein associated with protein translocation across the ER membrane. Northern blot analysis revealed its ubiquitous expression in all organs examined. We also localized the human beta-signal sequence receptor gene (SSR2) to chromosome bands 1q21-->q23 by fluorescence in situ hybridization.

Amino Acid Sequence↗
PubMed1995

Molecular cloning, characterization, and chromosomal mapping of a novel human gene (GTF3A) that is highly homologous to Xenopus transcription factor IIIA.

We have isolated a novel human cDNA that is highly related to Xenopus transcription factor IIIA (TFIIIA). This clone contains an open reading frame of 1,269 nucleotides encoding 423 amino acids, including nine repeats of the Cys2His2-type of zinc-finger domain. A comparison of its sequence with Xenopus TFIIIA revealed 63% identity in nucleic acids and 58% identity in amino acids over a large portion of the gene and predicted peptide, indicating that the human homologue is likely to function as a transcription factor. The zinc-finger domains of the predicted protein also showed homology with those of human genes such as WT1, transcriptional repressor YY1, and MYC-associated zinc-finger protein (MAZ). Northern analysis showed expression in various tissues examined. The human TFIIIA gene (GTF3A) was localized to chromosome band 13q12.3-->q13.1 by fluorescent in situ hybridization (FISH).

Amino Acid Sequence↗
PubMed1995

Isolation and mapping of a human gene (PDCD2) that is highly homologous to Rp8, a rat gene associated with programmed cell death.

From a human fetal lung cDNA library we isolated and characterized a human cDNA highly homologous to Rp8, a rat gene associated with programmed cell death. This cDNA, termed PDCD2 (programmed cell death-2), contained an open reading frame of 1032 nucleotides encoding 344 amino acids; it revealed 81% identity in DNA sequence and 83% identity in amino acid sequence with rat Rp8. The gene represented by PDCD2 was expressed in all human tissues examined. We assigned the PDCD2 locus to chromosomal band 6q27 by fluorescence in situ hybridization (FISH).

Amino Acid Sequence↗
PubMed1995

Development of intestinal flora of human-flora-associated (HFA) mice in the intestine of their offspring.

Development of intestinal flora in newborn human-flora-associated (HFA) mice was compared with that in newborn conventional (CV) mice. Facultative anaerobes were detected from the first day after birth in both CV and HFA mice but anaerobes were not detected in the first week. Anaerobes rapidly increased from the 2nd week after birth and became predominant in newborn intestine. Most of the intestinal bacteria in adult CV and HFA mice were colonized in the intestine of CV and HFA mice, respectively, within 3 weeks after birth. The human intestinal flora established in the intestine of HFA mice finally reproduced without any remarkable change in composition in the intestine of newborn HFA mice. The development of intestinal flora in HFA mice was similar to that in CV mice but not that in human infants. These results indicated that human flora associated in HFA mice could be transferred from mothers to their offspring although HFA mice could not simulate the development of intestinal flora of the human infant.

Adult↗
PubMed1995

Phosphonothrixin, a novel herbicidal antibiotic produced by Saccharothrix sp. ST-888. I. Taxonomy, fermentation, isolation and biological properties.

A novel herbicidal compound, phosphonothrixin, was found in the fermentation broth of Saccharothrix sp. ST-888 cultured on a vegetable juice medium. The compound exhibiting acidic and hydrophilic properties was obtained when the fermentation broth of ST-888 was subjected to ion exchange chromatography, gel filtration chromatography and ion-pair chromatography. Phosphonothrixin significantly inhibited germination of gramineous and broadleaf weeds. Foliar application of this antibiotic gave rise to chlorosis in all of the plants tested.

Actinomycetales↗
PubMed1995

Phosphonothrixin, a novel herbicidal antibiotic produced by Saccharothrix sp. ST-888. II. Structure determination.

Phosphonothrixin (1) is a novel herbicidal agent produced by Saccharothrix sp. ST-888. This unique compound possessing a C-P bond and an isoprene unit was determined to be 2-hydroxy-2-hydroxymethyl-3-oxobutyl-phosphonic acid. Unusually rapid proton-deuterium (H-D) exchange of the methyl ketone unit of this antibiotic in D2O solution was observed. Phosphonothrixin can be classified as a new type of natural product herbicide having a C-P bond in the molecule.

Actinomycetales↗