Biomedical subjects
Publications and source records attributed to M Iwami.
DNA segments carrying rRNA genes of Mycoplasma capricolum have been cloned and characterized by restriction endonuclease mapping, DNA-RNA hybridization and nucleotide sequencing. The M. capricolum genome has two sets of rRNA gene clusters, where the arrangement is in the order of (5')16S-23S-5S(3'). The spacer region between 16S and 23S rDNA is extremely rich in AT and does not carry any tRNA genes.
The nucleotide sequences of the rrnB 16S ribosomal RNA gene and its 5'-and 3'-flanking regions from Mycoplasma capricolum have been determined. The coding sequence is 1521 base pairs long, being 21 base pairs shorter than that of the Escherichia coli 16S rRNA gene. The 16S rRNA sequence of M. capricolum reveals 74% and 76% identify with that of E. coli and Anacystis nidulans, respectively. The secondary structure model constructed from the M. capricolum 16S rRNA gene sequence resembles that proposed for E. coli 16S rRNA. A large stem structure can be constructed between the 5'- and 3'-flanking sequences of the 16S rRNA gene. The flanking regions are extremely rich in AT.
WS-30581 A and B are antiplatelet agents produced by a strain of Streptoverticillium waksmanii. The compounds were purified by solvent extraction and column chromatography, and identified as new pimprinine analogs on the basis of their physico-chemical properties. The producing organism produced pimprinine along with these compounds. Pimprinine and the two new analogs have potent inhibitory effects on platelet aggregation.
Amauromine is a new alkaloid with vasodilating activity obtained from the culture broth of Amauroascus sp. No. 6237. Its molecular formula was determined to be C32H36N4O2 on the basis of elementary analysis and high resolution mass spectroscopic measurement. It has low toxicity in mice.
WF-5239 was produced by a fungal strain identified as Aspergillus fumigatus Fresenius. The substance was purified by solvent extraction followed by chromatography on silica gel and then crystallized (C9H9NO2, mp 142 approximately 145 degrees C). The chemical structure was determined from its physico-chemical properties as N-[2-cis(4-hydroxyphenyl)ethenyl]formamide. WF-5239 has inhibitory activity against rabbit platelet aggregation induced by arachidonic acid and collagen, with IC50 values of 1.25 and 5.0 micrograms/ml, respectively. Arachidonic acid induced mortality in mice was reduced by a single intraperitoneal dose of WF-5239 (30 mg/kg). These biological properties have been compared with those of aspirin.
FR-900109 is a new antibiotic obtained from fermentation broth of a streptomyces which was identified as Streptomyces prunicolor. Its elementary analysis and mass spectroscopic measurement suggest that the molecular formula is C27H32O9. It has an ultraviolet absorption maximum at 254 nm. The antibiotic is active against Gram-positive bacteria. Acute toxicity in mice is very low.
Explore the source record for details and available documents.
WF-3161 is an antitumor antibiotic produced by a strain of fungus, Petriella guttulata. The antibiotic was purified by solvent extraction and a combination of silica gel and reverse phase column chromatography. The chemical structure of the antibiotic (C31H44N4O6, mp 181-183 degrees C) was found to be a cyclic tetrapeptide consisting of phenylalanine, leucine, pipecolinic acid and 2-amino-8-oxo-9,10-epoxydecanoic acid. WF-3161 inhibited the growth of Trichophyton asteroides. It prolonged survival period of mice bearing leukemia P-388 with a high therapeutic index.
Explore the source record for details and available documents.
New vasodilators, designated WS-1228 A and B have been discovered in the culture filtrate of a strain of Streptomyces aureofaciens. The active compounds were purified by column chromatography with Diaion HP-20 and silica gel, and finally separated from each other by high performance liquid chromatography. They were obtained as pale yellow crystals and their molecular formulae were both C11H17N3O.
We report a 7-year-old girl with hemophagocytic lymphohistiocytosis and an uncommon complication of vascular retinopathy and visual sequelae. She was also verified to be complicated with dysfibrinogenemia. The patient was treated with etoposide, dexamethasone, and cyclosporin A. During the fifth hospital week, a generalized tonic-clonic convulsion developed followed by deep coma. When she regained full consciousness, she complained of a visual disturbance. The ophthalmologic examination showed bilateral extensive retinal edema with numerous cotton-wool spots, indicative of vaso-occlusive retinopathy. This is inconsistent with the main finding of previous cases with ocular involvement, namely papilledema. Severely reduced visual acuity and visual field defects remained in both eyes even after systemic therapy. An awareness of this rare but serious complication is important because it may be preventable by early institution of chemotherapy. The pathogenesis of the retinopathy is also discussed.
The nucleotide sequence of 5S rRNA from Mycoplasma capricolum is more similar to that of the gram-positive bacteria than that of the gram-negative bacteria. The presence of two copies of rRNA genes in M. capricolum genome has been demonstrated. The two different rRNA gene clusters have been cloned in E. coli plasmid vectors and analyzed for the rRNA gene organizations, demonstrating that the gene arrangement is in the order of 16S, 23S, and 5S rDNA. The ribosomes of M. capricolum contain about 30 species of proteins in 50S and 20 in 30S subunits. The number and size of the ribosomal proteins are not significantly different from those of other eubacterial ribosomes.