A new species of Streptomyces designated as Streptomyces indicus CHAKRABARTY which produces abundant aerial mycelium with shrimp-pink spores, antibiotic activity mainly against plant and human pathogenic fungi and melanin pigment, has been described. Its taxonomic relationship with other species of Streptomyces as well as the cultural, physiological and biochemical characteristics, are also discussed.
The growth inhibiting activity of the antibiotic showdomycin, a nucleoside derivative of maleimide, on E. coli Umezawa was specifically reversed by ribo- and deoxyribo-nucleosides and thiol compounds such as L-cysteine, glutathione and β-mercaptoethanol. No effect on the reversal of the anti bacterial activity of showdomycin was observed for purine, pyrimidine bases, nucleoside phosphates, ribose, deoxyribose and phosphate derivatives of ribose. Of the 19 amino acids tested, L-cysteine was the only one which is able to reverse the activity of showdomycin. All other amino acids were ineffective.
A new antibiotic, aristeromycin, was isolated from the culture filtrate of a new streptomyces, Streptomyces citricolor nov. sp. Aristeromycin is isolated using chromatography on active carbon, alumina and ion-exchange resin. Aristeromycin is isolated as colorless prism melting at 213-215°C (dec), and has the molecular formula C11H15O3N5. Its ultraviolet absorption maximum is observed at 262 mμ (El1%1cm 555). It shows inhibitory activities against Xantho monas oryzae and Piricularia oryzaein vitro as well as in vivo.
Formycin B, an inosine analogue, inhibits the incorporation of radioactive adenosine, uridine and thymidine, but none of formic acid, orotic acid and inorganic phosphoric acid into the cellular nucleic acid of Xanthomonas oryzae. The biochemical effects are readily reversed when formycin B is removed. Cell-free extract from the organism is entirely insensitive to formycin B in respect to phosphorylation of adenosine and thymidine. In consequence, it is likely that formycin B interferes with some process essential to entry of exogenous nucleosides into the cell. The lethal effect of formycin B on the organism is partially overcame by several nucleosides.
Studies on the structures of new components of leucomycin, A4(IV), A5(III), A6(VI), A7(V), A8(VIII) and A9(VII), were carried out in parallel with those on components A1(I) and A3(II), namely acetylation, and acid and alkaline hydrolysis. The pairs of components IV and III, VIandV, and VIIand VIII gave respectively, acetates X, XI and XIII. Components IV, VI and VIII had then respectively, 4-O-n-butyryl-, 4-O-propionyl- and 4-O-acetyl-mycarose replacing the 4-O-isovaleryl mycarose in the A3. Like A3, components IV, VI and VII had an O-acetyl group on C-3 of the 16-membered lactone.
Nitraminoacetic acid (C2H4N2O4) which showed partial inhibition of some gram-negative bacteria was produced by Streptomyces noursei 8054-MC3. It is extracted from culture filtrate with butanol and after chromatographic purification it is recrystallized from mixed solvent of ethylacetate and chloro form as colorless needles. It is acidic and melts at 106°C. Physicochemical properties including n.m.r., infrared and ultraviolet spectra, and its chemical synthesis are also reported.
In taxonomic studies on two streptomyces, the strain MCRL-0357 which produces the antibiotic BD-12 was recognized to be a new species of streptomyces and named Streptomyces luteocolor nov. sp. The strain MCRL-0358 which produces antibiotic BY-81 was concluded to be a new variety of Streptomyces olivoreticuli ARAI et al. The production of both antibiotics were described.
The preparation and properties of a new series of penicillins, 6-(3-substi tuted sydnone-4-carboxamido)penicillanates, are described. Those of the new penicillins having an aryl group at 3-position of sydnone ring showed activity against a penicillinase-producing organism. These penicillins are, however, not very resistant to penicillinase when compared with oxacillin.
6-(Sydnone-3-acetamido) penicillanates and 7-(sydnone-3-acetamido) cepha losporanates were prepared by N-acylation of 6-APA or 7-ACA with sydnone 3-acetyl chloride. The new series of semi-synthetic antibiotics were compared with ampicillin and cephalothin. Sydonylmethylpenicillin (BBP-425) and sydnonylmethylcephalosporin (BBP-428) were active against gram-positive and gram-negative microbes both in vitro and in vivo.