Search PubMed⌕ Search

Biomedical subjects

Y Yasuda

Publications and source records attributed to Y Yasuda.

At least 415 records · Page 23Linked to original sources
PubMed1979

Nucleotide sequence of Escherichia coli K-12 replication origin.

From subfragments of an EcoRI fragment (9 kilobase pairs) that contained the replication origin of the Escherichia coli chromosome and had been cloned as a recombinant with a nonreplicating DNA fragment coding for ampicillin resistance, small derivative plasmids were constructed. The smallest of these, pTSO151, contained a segment of 463 base pairs as the chromosomal component. Another plasmid, pSY134, constructed from BamHI digests of the EcoRI fragment and mini-F(pMF21), contained a region of 422 base pairs identical with a corresponding region in pTSO151. We conclude that the replication origin of E. coli chromosome is located within this 422-base-pair segment. The nucleotide sequence of this segment is presented.

Base Sequence↗
PubMed1979

Difference in capacity of Sendai virus envelope components to induce cytotoxic T lymphocytes in primary and secondary immune responses.

Studies were made on the abilities of Sendai virus envelope components to induce primary and secondary generations of virus-specific cytotoxic mouse T lymphocytes (CTL). The primary CTL response in BALB/c mice was induced by reassembled envelope particles that had fusion activity but not by envelope glycoproteins without fusion activity, although both preparations induced a humoral immune response. Reconstitution of membrane-bound envelope proteins from envelope glycoproteins with lipids restored the fusion activity and the capacity to induce CTL. Target cells susceptible to virus-specific CTL could be induced by reassembled envelope particles, but not by envelope glycoproteins or LLC-MK2 cell-grown Sendai virus, neither of which had fusion activity. On the other hand, all the viruses and envelope components tested were found to stimulate a virus-specific CTL response in the in vitro secondary generation of CTL from virus-primed spleen cells. These results suggest that Senaei virus fusion activity is involved in primary induction of the CTL response as well as in target cell formation, but that it is not essential for secondary stimulation of the CTL response.

Animals↗
PubMed1978

Disappearance of cortical granules in rat ovum in vivo following fertilization.

Electron microscopical studies of the rat ova were carried out to clarify the pattern of disappearance of cortical granules following fertilization. When the posterior cap of the head of a spermatozoon was attahced to the vitelline membrane, cortical granules located beneath this membrane fused with this membrane to be decomposed or broken. Then their contents were discharged into the perivitelline space. The disappearance of cortical granules seemed to have started in an area around the site of the vitelline membrane to which spermatozoon was attached and spread soon all over the vitellus.

Animals↗
PubMed1978

The metabolism of a bronchodilator procaterol HCL in the rat in vitro and in vivo.

1. The metabolism of the bronchodilator, 5-(1-hydroxy-2-isopropylamino-butyl)-8-hydroxycarbostyril hydrochloride hemihydrate (procaterol HCl), has been studied in vitro and in vivo after oral and intravenous administration to rats. 2. The recovery of [14 C] procaterol HCl and its metabolites in 72 h was about 42% each in urine and faeces for an oral dose (30 mg/kg) and about 53% in urine and 33% in faeces for an intravenous dose (30 mg/kg). 3. Six metabolites in rat excreta were identified as procaterol glucuronide, 5-(2-amino-1-hydroxybutyl)-8-hydroxycarbostyril (desisopropylprocaterol), 5-formyl-8-hydroxycarbostyril (5-formyl-8-HCS), 8-hydroxycarbostyril (8-HCS), procaterol sulphate and unchanged procaterol. 4. In experiments in vitro, procaterol HCl was metabolized into desisopropylprocaterol, 5-formyl-8-HCS, and their conjugates, by rat liver 9000 g supernatant fraction, but not by preparations of kidney, lung and small intestine. Conjugation of procaterol HCl with glucuronic acid occurred in liver and small intestine preparations.

Amino Alcohols↗
PubMed1977

Effect of prenatal treatment with ethinyl estradiol on the mouse uterus and ovary.

Oral ethinyl estradiol (0.01 or 0.02 mg. per kilogram) administered prenatally to ICR-JCL strain mice before the development of the uterine and ovarian blastemata induced cystic glandular hyperplasia with epidermization in the endometrium and excessive formation of degenerating follicles in the ovaries at 10 to 14 weeks of age. To the evidence for the production by estrogen of malignant uterine neoplasms in rodents and the clinical data showing that cystic glandular hyperplasia develops after prolonged estrogen administration in postmenopausal women and adenocarcinoma in premenopausal or menopausal women using oral contraceptives including ethinyl estradiol, we add the present results which suggest that ethinyl estradiol administered transplacentally can cause malignant transformation of the uterine endometrium in mice.

Animals↗
PubMed1977

RNA synthesis in isolated nuclei of Xenopus laevis emproyos.

Nuclei were isolated from tailbud embryos of Xenopus laevis and their RNA synthetic activity was studied. The activity was sensitive to actinomycin D, and required the presence of all four ribonucleotide triphosphates and a divalent cation (Mg2+ or Mn2+). The effect of the divalent cation varied depending on the presence of 0.4 M KCl: in its absence more RNA was synthesized with Mg2+ than with Mn2+, but in its presence the situation was reversed. About 50% of the RNA synthesized was sensitive to the presence of alpha-amanitin. Polyacrylamide gel electrophoresis of the labeled RNA revealed that the RNA synthesized had a very heterogeneous size distribution ranging from 40 to 4 S, with a broad peak at around 28--18 S. The RNA which was distributed at around 28--18 S and 4 S was resistant to the presence of a low dose of alpha-amanitin, suggesting its ribosomal and soluble RNA nature. The RNA which was sensitive to this drug and hence may be assumed to be messenger RNA was distributed mainly between 18 and 4 S. From these results it appears that the isolated embryonic nuclei retain their activity to synthesize all of the major classes of RNA.

Amanitins↗
PubMed1977

Digital anomalies of mouse limbs induced by treatment with urethan in vitro.

The effects of urethan on ICR/JCL mouse limbs were examined in forelimbs of day-11 embryos cultured in concentrations of 0, 50, and 100 mug/ml for one to four days, and in forelimbs of day-12 embryos and in fore- and hind limbs of day-13 embryos in 0, 10, 50, and 100 mug/ml for one to four days. Urethan did not cause digital malformations on day-11 limbs but induced syndactyly in day-12 forelimbs and polydactyly in day-12 forelimbs and day-13-fore- and hind limbs. The polydactyly may have been due to effects on mesenchymal cells producing localized cell proliferation, whereas syndactyly may have been due to effects on precartilage cells, resulting in excess migration of mesenchymal cells toward the digits, leaving the connective tissue at the interdigital space to develop inadequately.

Abnormalities, Drug-Induced↗
PubMed1975

Antibiotic A-130, isolation and characterization.

An antibiotic, A-130, was isolated from a strain identified as Streptomyces hygroscopicus, strain A-130. The antibiotic belongs to the nigericin group and like dianemycin, has an alpha, beta-unsaturated ketone chromophore in its molecule. A-130 is active against gram-positive organisms.

Anti-Bacterial Agents↗