Synthesis and content of ether-linked glycerophospholipids in the harderian gland of rabbits.

Although harderian glands are rich in neutral glycerolipids with ether bonds, less than 20% of the choline glycerophospholipids have ether bonds in the white and pink portions of the adult rabbit harderian gland. Only 6% of these are plasmalogens while 94% are alkylacyl glycerophosphocholines. The ethanolamine glycerophospholipids include 37% with ether bonds in both white and pink portions. In the white portion 96% are plasmalogens but only 19% are plasmalogens in the pink portion. The microsomal ethanolaminephosphotransferase (EC 2.7.8.1) is more active with diacylglycerols than with alkylacylglycerols. The microsomal cholinephosphotransferase (EC 2.7.8.2) is equally active with both diradylglycerols. Particularly with microsomes from the pink portion, the apparent Km values for CDPethanolamine and CDPcholine are ower in the presence of alkylacylglycerols than in the presence of diacylglycerols. The incorporation of radioactivity from CDP[14C]ethanolamine and CDP[14C]choline into ethanolamine and choline plasmalogens was increased several-fold by addition of alkylacylglycerols but was not increased substantially by addition of diacylglycerols.

Studies on the ionophorous antibiotics. XXV. The assignments of the 13C-NMR spectra of dianemycin and lenoremycin.

All the resonances observed in the 13C-NMR spectra of polyether antibiotics, dianemycin and lenoremycin (Ro 21-6150) have been assigned by the aid of selective proton decoupling experiments, T1 value measurements and biosynthetic methods as well as comparison to model compounds such as monensin, nigericin, etheromycin and carriomycin.

Ionomycin, a new polyether antibiotic.

Ionomycin, a new polyether antibiotic with a high affinity for calcium ions, is obtained in pure form from fermentation broths of Streptomyces conglobatus sp. nov. Trejo by solvent extraction. It is unique amongst known polyether antibiotics in that it has a UV absorption maximum at 300 nm. thereby distinguishing it from other antibiotics of its class. The Ca salt has the molecular formula C41H70O9Ca. Ionomycin is a narrow spectrum antibiotic being active against Gram-positive bacteria.

Noboritomycins A and B, new polyether antibiotics.

Noboritomycins A and B, two new polycyclic ionophoric polyethers were isolated from a strain of Streptomyces noboritoensis. The crystal structure and absolute configuration of noboritomycin A were established by X-ray analysis of its silver salt C43/63O14Ag. Noboritomycin A is the first metabolic polyether possessing two carboxylic acid functions on the carbon backbone (C-31), namely a free acid and an additional carboxylic acid ethylester group. An unusual spiroketal system as well as a salicylic acid chromophore represent further remarkable elements. Noboritomycin A shows in this respect a structural relationship to salinomycin and lasalocid respectively. Comparison of physico-chemical data, in particular the interpretation of the 1H- and 13C-NMR spectra, revealed that noboritomycins A and B are structurally closely related, noboritomycin B carrying an ethyl substituent on the aromatic ring in the place of a methyl group present in noboritomycin A. Both metabolites exhibit activity against Gram-positive bacteria and against Eimeria tenella (chicken coccidiosis).

Studies on the ionophorous antibiotics. XXIV. Leuseramycin, a new polyether antibiotic produced by Streptomyces hygroscopicus.

A new antibiotic leuseramycin has been isolated from the cultured mycelium of the strain of Streptomyces hygroscopicus TM-531. Physicochemical data, in particular those of 1H- and 13C-NMR spectra, revealed that leuseramycin is closely related to dianemycin in its structure, the former having a methyl group in place of the hydroxymethyl group at C-30. It is active against Gram-positive bacteria, some phytopathogenic fungi and some protozoa.

Ferensimycins A and B. Two polyether antibiotics. Taxonomy, fermentation, isolation, characterization and structural studies.

Ferensimycin A* (I), C34H59O10Na, mp 133 approximately 135 degrees C, and ferensimycin B** (II), C35H61O10Na, mp 143 approximately 145 degrees C, were isolated as their sodium salts from the fermentation broth of Streptomyces sp. No. 5057, a strain similar to Streptomyces myxogenes Shomura et al. The physicochemical data of I and II showed that they are both closely related congeners of lysocellin (III). Ferensimycins A and B exhibit activity against Gram-positive bacteria and are effective in the treatment of coccidiosis of fowl.

Antibiotic DE-3936, a polyether antibiotic identical with lonomycin. Taxonomy, fermentation, isolation and characterization.

Antibiotic DE-3936 was isolated from the fermentation broth of a streptomycete No. 9735-1, which is identified as a strain of Streptomyces hygroscopicus. The antibiotic is a hydrophobic compound having the molecular formula of of C44H75O14Na and is active against Gram-positive bacteria, mycobacteria, mycoplasma and protozoa, especially coccidia. Its chemical and biological properties indicate that antibiotic DE-3936 belongs to the group of polyether antibiotics and is identical with lonomycin.