PubMed Health⌕ Search

Biomedical subjects

H Seto

Publications and source records attributed to H Seto.

At least 307 records · Page 17Linked to original sources
PubMed1986

13C NMR evidence for bacteriochlorophyll c formation by the C5 pathway in green sulfur bacterium, Prosthecochloris.

The 13C NMR spectra of the pheophorbide of bacteriochlorophyll c, formed in the presence of L-[1-13C]glutamate and [2-13C]glycine and [13C]bicarbonate in Prosthecochloris aestaurii, were analysed. The isotope in the glutamate was specifically incorporated into the eight carbon atoms in the tetrapyrrole macrocycle derived from the C-5 of 5-aminolevulinic acid, while no specific enrichment of these eight carbon atoms was observed in the spectrum of the pigment formed in the presence of [2-13C]glycine. These labelling patterns provide evidence for the operation of the C5 pathway of 5-aminolevulinic acid synthesis for bacteriochlorophyll c formation in the bacterium. The labelling of bacteriochlorophyll c by [13C]bicarbonate is consistent with its formation from 5-[1,4,5-13C]aminolevulinic acid formed by the C5 pathway from [1,2,5-13C]glutamic acid. It is proposed that this glutamate is the transamination product of 2-[1,2,5-13C]oxoglutaric acid, arising by carboxylation of [1,4-13C]succinyl-CoA with 13CO2 catalysed by 2-oxoglutaric acid synthase activity, and that the labelled succinyl-CoA is, in turn, derived by the fixation of 13CO2 by the reductive tricarboxylic acid cycle. The 13C chemical shifts of two sp2 quaternary carbons of bacteriopheophorbide c methyl ester (C-2 and C-4) were reassigned.

Bacteria↗
PubMed1986

13C-NMR evidence of bacteriochlorophyll a formation by the C5 pathway in Chromatium.

The 13C-NMR spectra of bacteriochlorophyll a formed in the presence of L-[1-13C]glutamate and [2-13C]glycine in Chromatium vinosum strain D were analyzed. The isotope in the glutamate was specifically incorporated into eight carbon atoms in the tetrapyrrole macrocycle derived from the C-5 of 5-aminolevulinic acid (ALA), and the 13C in glycine was incorporated into the methyl carbon of the methoxycarbonyl group attached to the isocyclic ring of bacteriochlorophyll a. These labeling patterns provide evidence for the exclusive operation of the C5 pathway in ALA biosynthesis in the bacterium. The 13C chemical shifts of two quaternary carbons (C-9 and C-16) of bacteriochlorophyll a were reassigned in the present study.

Aminolevulinic Acid↗
PubMed1986

Capuramycin, a new nucleoside antibiotic. Taxonomy, fermentation, isolation and characterization.

A new antibiotic capuramycin was isolated from the culture filtrate of Streptomyces griseus 446-S3 by adsorption and partition column chromatography. Based on its chemical structure being an uracil nucleoside with a caprolactam substituent, this substance was named as capuramycin. This paper describes the taxonomy of a producing organism, fermentation, isolation, characterization and biological properties of capuramycin.

Aminoglycosides↗
PubMed1986

A novel macrolide antibiotic, notonesomycin A.

Fermentation of Streptomyces aminophilus subsp. notonesogenes 647-AV1 produced a mixture of antifungal antibiotics. Notonesomycin A, the main component has been characterized as a new macrolide antibiotic containing a sulfate group, a malonate moiety, two deoxysugars and a 1,3,4-trisubstituted benzene system in the molecule. It was active against some fungi and Gram-positive bacteria in vitro and effective against the sheath blight disease of rice plant in a green house test.

Animals↗