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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

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↗
PubMed1994

Structure and regulation of the human interferon regulatory factor 1 (IRF-1) and IRF-2 genes: implications for a gene network in the interferon system.

Interferon regulatory factor 1 (IRF-1) and IRF-2 are structurally similar DNA-binding factors which were originally identified as regulators of the type I interferon (IFN) system; the former functions as a transcriptional activator, and the latter represses IRF-1 function by competing for the same cis elements. More recent studies have revealed new roles of the two factors in the regulation of cell growth; IRF-1 and IRF-2 manifest antioncogenic and oncogenic activities, respectively. In this study, we determined the structures and chromosomal locations of the human IRF-1 and IRF-2 genes and further characterized the promoters of the respective genes. Comparison of exon-intron organization of the two genes revealed a common evolutionary structure, notably within the exons encoding the N-terminal portions of the two factors. We confirmed the chromosomal mapping of the human IRF-1 gene to 5q31.1 and newly assigned the IRF-2 gene to 4q35.1, using fluorescence in situ hybridization. The 5' regulatory regions of both genes contain highly GC-rich sequences and consensus binding sequences for several known transcription factors, including NF-kappa B. Interestingly, one IRF binding site was found within the IRF-2 promoter, and expression of the IRF-2 gene was affected by both transient and stable IRF-1 expression. In addition, one potential IFN-gamma-activated sequence was found within the IRF-1 promoter. Thus, these results may shed light on the complex gene network involved in regulation of the IFN system.

Animals↗
PubMed1994

Clinical and experimental studies of anti-tumoural effects of electrochemical therapy (ECT) alone or in combination with chemotherapy.

The present experimental study shows that anticancer agents may accumulate around electrodes placed in saline and in lung when the electrodes are charged with direct electric current. We also observed that electrochemical therapy (ECT) in combination with chemotherapy was more effective for treatment of localized tumours (human lung cancer PC-13 transplated to nude mice) than was ECT or systemic chemotherapy alone. In a clinical study, 26 patients (27 lesions) received ECT with or without systemic chemotherapy. We observed a decrease in tumour size in more than 70% of the cases, and in two cases the use of ECT alone resulted in complete regression of the tumour. In one case there was an increase in tumour size. The main side-effects observed during treatment of lung cancer was pain during treatment, fever after treatment, and pneumothorax. We conclude that ECT may be effective in controlling localised tumours. The clinical use of ECT is, however, associated with several problems and the mechanism of this treatment has not yet been completely established.

Adult↗
PubMed1992

Genomic structure of the human caldesmon gene.

The high molecular weight caldesmon (h-CaD) is predominantly expressed in smooth muscles, whereas the low molecular weight caldesmon (l-CaD) is widely distributed in nonmuscle tissues and cells. The changes in CaD isoform expression are closely correlated with the phenotypic modulation of smooth muscle cells. During a search for isoform diversity of human CaDs, l-CaD cDNAs were cloned from HeLa S3 cells. HeLa l-CaD I is composed of 558 amino acids, whereas 26 amino acids (residues 202-227 for HeLa l-CaD I) are deleted in HeLa l-CaD II. The short amino-terminal sequence of HeLa l-CaDs is different from that of fibroblast (WI-38) l-CaD II and human aorta h-CaD. We have also identified WI-38 l-CaD I, which contains a 26-amino acid insertion relative to WI-38 l-CaD II. To reveal the molecular events of the expressional regulation of the CaD isoforms, the genomic structure of the human CaD gene was determined. The human CaD gene is composed of 14 exons and was mapped to a single locus, 7q33-q34. The 26-amino acid insertion is encoded in exon 4 and is specifically spliced in the mRNAs for both h-CaD and l-CaDs I. Exon 3 is the exon that encodes the central repeating domain specific to h-CaD (residues 208-436) together with the common domain in all CaD (residues 73-207 for h-CaD and WI-38 l-CaDs, and residues 68-201 for HeLa l-CaDs). The regulation of h- and l-CaD expression is thought to depend on selection of the two 5' splice sites within exon 3. Thus, the change in expression between l-CaD and h-CaD might be caused by this splicing pathway.

Alternative Splicing↗
PubMed1992

Structure and chromosomal localization of human arachidonate 12-lipoxygenase gene.

Arachidonate 12-lipoxygenase introduces a molecular oxygen into the C-12 position of arachidonic acid to produce 12(S)-hydroperoxy-5,8,10,14-eicosatetraenoic acid. With the aid of cDNA probes for the enzyme, we isolated overlapping lambda clones encompassing the human 12-lipoxygenase gene and flanking regions from a human genomic library. The gene consists of 14 exons with 13 introns and spans approximately 15 kilobases of DNA. All the exon-intron junctions conform to the GT/AG rule. Neither a typical TATA box nor a CAAT box was found in approximately 1-kb sequence of 5'-upstream region of the translation initiation site. However, this region contains several regulatory elements including four GC boxes, two CACCC boxes, three AP-2 binding sequences, and a glucocorticoid-responsive element. The major transcription initiation site was determined by primer-extension analysis as an adenosine residue at 306 bases upstream from the translation initiation codon. The chromosomal localization of the human 12-lipoxygenase gene was examined by fluorescence in situ hybridization, and the gene was assigned to the sub-band p13.1 of chromosome 17.

Arachidonate 12-Lipoxygenase↗
PubMed1992

Isolation and sequence determination of cDNA encoding PMP-22 (PAS-II/SR13/Gas-3) of human peripheral myelin.

A full length cDNA of PMP-22 (PAS-II/SR13/Gas-3) of peripheral myelin has been isolated from a cDNA library of human fetus spinal cord. The clone is 1823 base pairs (bp) in length and contains a 480 bp open reading frame encoding a polypeptide of 160 residues. The deduced amino acid sequence is highly homologous to PMP-22 from bovine (PAS-II), rat (SR13) and mouse (Gas-3).

Amino Acid Sequence↗
PubMed1992

Molecular cloning of genomic DNA and chromosomal assignment of the gene for human aromatic L-amino acid decarboxylase, the enzyme for catecholamine and serotonin biosynthesis.

Aromatic L-amino acid decarboxylase (AADC) catalyzes the decarboxylation of both L-3,4-dihydroxyphenylalanine and L-5-hydroxytryptophan to dopamine and serotonin, respectively, which are major mammalian neurotransmitters and hormones belonging to catecholamines and indoleamines. This report describes the organization of the human AADC gene. We proved that the gene of human AADC consists of 15 exons spanning more than 85 kilobases and exists as a single copy in the haploid genome. The boundaries between exon and intron followed the AG/GT rule. The sizes of exons and introns ranged from 20 to 400 bp and from 1.0 to 17.7 kb, respectively, while the sizes of four introns were not determined. Untranslated regions located in the 5' region of mRNA were encoded by two exons, exons 1 and 2. The transcriptional starting point was determined around G at position -111 by primer extension and S1 mapping. There were no typical "TATA box" and "CAAT box" within 540 bp from the transcriptional starting point. The human AADC gene was mapped to chromosome band 7p12.1-p12.3 by fluorescence in situ hybridization. This is the first report on the genomic structure and chromosomal localization of the AADC gene in mammals.

Amino Acid Sequence↗
PubMed1992

Proton and electron transfer in the acceptor quinone complex of Rhodobacter sphaeroides reaction centers: characterization of site-directed mutants of the two ionizable residues, GluL212 and AspL213, in the QB binding site.

Proton and electron transfer events in reaction centers (RCs) from Rhodobacter sphaeroides were investigated by site-directed mutagenesis of glutamic acid at position 212 and aspartic acid at 213 in the secondary quinone (QB) binding domain of the L subunit. These residues were mutated singly to the corresponding amides (mutants L212EQ and L213DN) and together to give the double mutant (L212EQ/L213DN). In the double mutant RCs, the rate of electron transfer from the primary (QA) to the secondary (QB) acceptor quinones is fast (tau approximately 300 microseconds) and is pH independent from pH 5 to 11. The rate of recombination between the oxidized primary donor, P+, and QB- is also pH independent and much slower (tau approximately 10 s) than in the wild type (Wt), indicating a significant stabilization of the QB- semiquinone. In the double mutant, and in L213DN mutant RCs at low pH, the P+QB- decay is suggested to occur significantly via a direct recombination rather than by repopulating the P+QA- state, as in the Wt. Comparison of the behavior of Wt and the three mutant RC types leads to the following conclusions: the pK of AspL213 in the Wt is approximately 4 for the QAQB state (pKQB) and approximately 5 for the QAQB-state (pKQB-); for GluL212, pKQB approximately 9.5 and pKQB- approximately 11. In L213DN mutant RCs, pKQB of GluL212 is less than or equal to 7, indicating that the high pK values of GluL212 in the Wt are due largely to electrostatic interaction with the ionized AspL213 which contributes a shift of at least 2.5 pH units. Transfer of the second electron and all associated proton uptake to form QBH2 is drastically inhibited in double mutant and L213DN mutant RCs. At pH greater than or equal to 8, the rates are at least 10(4)-fold slower than in Wt RCs. In L212EQ mutant RCs the second electron transfer and proton uptake are biphasic. The fast phase of the electron transfer is similar to that of the Wt, but the extent of rapid transfer is pH dependent, revealing the pH dependence of the equilibrium QA(-)QB- in equilibrium with QAQBH-. The estimated limits on the pK values--pKQA-QB-less than or equal to 7.3, pKQAQB2- greater than or equal to 10.4--are similar to those derived earlier for Wt RCs [Kleinfeld et al. (1985) Biochim. Biophys. Acta 809, 291-310] and may pertain to the quinone head group, per se.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1992

Identification and nucleotide sequence of a gene in feline herpesvirus type 1 homologous to the herpes simplex virus gene encoding the glycoprotein B.

The nucleotide sequence of the glycoprotein B (gB) homologous gene of feline herpesvirus type 1 (FHV-1) was determined. The gene was found to be located within a 9.6 kbp SalI fragment by Southern-blot hybridization with a probe derived from the herpes simplex virus type 1 (HSV-1) gB DNA sequence. Furthermore, the predominant portion of the coding sequences was mapped to a 1.9 kbp Hin cII-EcoRI and its flanking 2.7 kbp Eco RI-Eco RI subfragments in the 9.6 kbp SalI fragment. The entire nucleotide sequence revealed that the FHV-1 gB homologous gene is capable of encoding a polypeptide of 948 amino acids. The predicted precursor polypeptide derived from this open reading frame could have a calculated M(r) of 106 kDa in unglycosylated form and contains ten potential N-linked glycosylation sites and a probable internal proteolytic cleavage site. By Northern-blot analysis using portions of the open reading frame as a probe, 3.9 and 3.3 kb RNA transcripts were identified in FHV-1 infected cells. The alignment of the amino acid sequence of the FHV-1 gB homologue with those of 14 other herpesviruses revealed that 10 cysteine residues were completely conserved. Meanwhile, when evolutionary trees were generated among these herpesvirus gB counterparts, the FHV-1 gB homologous nucleotide sequence seems to be closely related to equine herpesvirus type 4 and its amino acid sequence to pseudorabies virus.

Amino Acid Sequence↗
PubMed1992

Heterogeneity of feline herpesvirus type 1 strains.

Heterogeneity of 9 feline herpesvirus type 1 (FHV-1) strains consisting of the prototype C27 strain, one French isolate, six Japanese isolates, and the attenuated vaccine F2 strain was examined by biological, immunological, and molecular biological methods. No significant difference was observed in virus growth and antigenic properties among the strains in Crandell feline kidney cell cultures. Hemagglutination activity was also detected in all extracts of cells infected with each strain. However, in immunoblot analysis, a virus-structural immunogenic protein with an M(r) of 36 kDa was lacking in 2 strains, one of which was the vaccine F2 strain, whereas the other immunogenic proteins including three kinds of major glycoproteins were detected in all strains without differences in electrophoretic mobilities. Furthermore, when restriction endonuclease analysis was performed to examine the genomic heterogeneity of strains, the cleavage patterns with the enzyme MluI showed a genomic heterogeneity between wild and vaccine strains. In contrast, only a slight variation in the sizes of some fragments was shown with most of the 7 other enzymes used. These results indicated that the lack of the 36 kDa protein and the MluI cleavage pattern could be used as markers of the vaccine F2 strain. The specific markers are important not only to control the quality of the vaccine but also to evaluate the vaccine immunity in FHV-1 infection in cats.

Animals↗
PubMed1992

Glycoprotein-specific immune response in canine herpesvirus infection.

Sera from dogs which were infected with canine herpesvirus (CHV) were analyzed for their serological reactivities against virus-specific glycoproteins (gps). By sequential immunoblot analysis using sera from experimentally infected dogs, it was found that the antibody response to gp 145/112 appeared first followed by responses to gp47 and gp80. In addition, all sera from naturally infected dogs which showed neutralizing activity to CHV reacted with gp 145/112, whereas 77% and 70% reacted with gp47 and gp80, respectively. Furthermore, some of the sera also cross-neutralized feline herpesvirus type 1 (FHV-1) and reacted with gp 143/108 of FHV-1, indicating that gp 145/112 of CHV induced cross-neutralizing antibody response to FHV-1.

Animals↗
PubMed1992

Expression of feline immunodeficiency virus gag gene in Escherichia coli.

The gag gene of a Japanese feline immunodeficiency virus (FIV) isolate, designated as FIV TM 2, was expressed in Escherichia coli as a fusion protein with TrpE. Using this expressed protein, an enzyme-linked immunosorbent assay was developed for detection of antibodies to FIV gag protein in feline sera. With serum samples from a cat experimentally infected with FIV, it was demonstrated that the period of seroconversion detected by this method corresponded to that by Western blotting.

Cloning, Molecular↗
PubMed1992

Localization of PMP-22 gene (candidate gene for the Charcot-Marie-Tooth disease 1A) to band 17p11.2 by direct R-banding fluorescence in situ hybridization.

We mapped PMP-22 gene, candidate gene for the Charcot-Marie-Tooth disease (CMT) 1A, by direct R-banding fluorescence in situ hybridization. The signals of PMP-22 probe were localized to chromosome band 17p11.2. The present result was within the map position of the CMT 1A gene by genetic linkage analysis, and strongly indicated that PMP-22 gene is a candidate gene for the CMT 1A.

Charcot-Marie-Tooth Disease↗
PubMed1992

Expressivity of a common fragile site, fra(3)(p14.2), in patients with cancer and other diseases.

A population survey of a common folate-sensitive fragile site, fra(3)(p14.2), has been carried out on PHA-stimulated peripheral lymphocytes of patients with cancer and other diseases, under both culture conditions of folate deprivation and aphidicolin treatment. Overall findings regarding variability of expressivity due to age and sex were very similar to those obtained in a healthy population. The expression of fra(3)(p14.2) by folate deficient condition appeared hardly influenced by such exogenous factors as tobacco smoking habit, past histories of radiotherapy and chemotherapy, while it was associated with the unfavorable prognosis of cancers. Furthermore, proportion of those with higher expression was slightly but significantly larger in both lung and breast cancer patients. These findings suggest that some factors relevant to the expression of fra(3)(p14.2) may be associated with development and progression of certain kinds of cancer.

Adolescent↗
PubMed1992

Chromosome abnormalities and rare fragile sites detected in azoospermia patients.

We have examined constitutional chromosome abnormalities and fragile sites in 40 patients with azoospermia. Chromosome abnormalities were found in four cases. Three cases showed a deletion of the long arm of the Y chromosome 46,X,del(Yq) and the other case had a ring of G group chromosome 46,XY,r(G). In a rare fragile sites test, four fragile site carriers were detected and three rare autosomal fragile sites were identified; fra(8)(q24.1), fra(11)(p15.1), and fra(17)(p12). The expression of these fragile sites were induced specifically by AT-specific DNA ligands, such as distamycin A and Hoechst 33258. In addition, one patient was found to be the case of double ascertainment of fragile sites, fra(8)(q24.1) and fra(17)(p12). The overall frequency of distamycin A-inducible fragile sites in azoospermia patients appeared to be higher than those reported for Japanese healthy subjects and cancer patients. However, no significant relation among fragile sites, clinical and histological findings has been detected so far.

Chromosome Aberrations↗