[Synthesis and antibacterial activity of perchlorylchloramphenicol]. / Synthese und antibakterielle Aktivität von Perchlorylchloramphenicol.

Starting from p-perchloryl acetophenone we have synthesized the perchloryl analogue of chloramphenicol. The new compound is the first chloramphenicol analogue possessing a higher antimicrobial activity as chloramphenicol itself. It showed an about twofold activity against 18 different microbes in the hole plate diffusion test, compared with the parent compound.

Sarubicin b, a new quinone antibiotic, isolated from the fermentation broth of a streptomyces strain.

Sarubicin B, isolated from the culture filtrate of a Streptomyces strain JA 2861, is a new quinone antibiotic. The compound was isolated as an orange crystalline powder, mp 282 approximately 284 degrees C. In vitro sarubicin B was found to inhibit Gram-positive bacteria. It was not active against Gram-negative microorganisms.

[Use of automated image analysis for screening the efficiency of turimycin-producing Streptomyces strains]. / Einsatz der automatischen Bildanalyse beim Screening von leistungsfähigen Selektanten Turimycin-bildender Streptomyces-Stämme.

The growth of the surface colonies on solid media is studied with the image analyzing system Quantimet 720 M controlled by a PDP 11 computer. For the bacterial strain Streptomyces hygroscopicus JA 6599 a new differential equation describing the kinetic behaviour of the area of the colony is suggested. It is shown that this time dependence of area describes more realistically the experiment than the function resulting from Pirt's model. Two new constants arise from the growing curve, alpha describes the profile of density of the colony and k0 is correlated to the growing constant of the colony. Both parameters can be correlated to the amount of antibiotics produced and, therefore, it is possible to use this information for the selection procedure of the colonies. A uniform criterion for selection was found for each colony of two mutants of the turimycin-producing strain Streptomyces hygroscopicus JA 6599, which reads: (Formula: see text). The quality of the selection criterion of surface colonies with higher productivity is dependent on the mean value of the growing parameters of all colonies under investigation. Limitations of the selection method arise from the need for great uniformity of environmental conditions, growth medium and a homogeneous spore suspension, which have to consist of a large amount of single spores in order to assure a reproducible growing curve of the colonies. For the last condition a special technique is pointed out.

Isolation and characterization of sarubicin A, a new antibiotic.

The new antibiotic sarubicin A [red crystals, mp. 194 approximately 195 degrees C, C18H14N2O6 (I)] was isolated from fermentations of a Streptomyces strain. The compound is moderately active in vitro against Micrococcus luteus.

[Comparative clinical and experimental studies of various denture cleansers. 2. Testing of antimicrobial efficiency]. / Vergleichende klinische und experimentelle Untersuchungen verschiedener Prothesenreinigungsmittel 2. Mitteilung: Prüfung der antimikrobiellen Wirksamkeit

Agar diffusion plate tests were performed on five strains of micro-organisms to characterize the disinfecting properties of nine denture cleaners. Furthermore, the liberation of oxygen was determined as a function of time, and the course of pH variation of the various cleaning solutions was studied. The highest oxygen concentrations and the best antimicrobic activities were achieved by the preparations Eladent G and T.

Streptovirudins, new antibiotics with antibacterial and antiviral activity. I. Culture taxonomy, fermentation and production of streptovirudin complex.

A new antibiotic complex has been isolated from cultures of Streptomyces strain No. JA 10124. On the basis of taxonomic studies, the producing microorganism is described as Streptomyces griseoflavus (Krainsky, 1914) Waksman et Henrici, 1948, subsp. thuringiensis subsp. nov., type strain JA 10124. The antibiotic complex, designated as streptovirudin, was isolated from extracts of both mycelium and culture filtrate. It is a white amorphous material which consists of ten closely related components including streptovirudins A, B, C, D and E. The streptovirudin complex exhibits antibiotic activity against Gram-positive bacteria, mycobacteria, and various DNA- and RNA-viruses.

Streptovirudins, new antibiotics with antibacterial and antiviral activity. II. Isolation, chemical characterization and biological activity of streptovirudins A1, A2, B1, B2, C1, C2, D1, and D2.

Streptovirudin is a complex of antibiotics isolated from fermentation of a Streptomyces strain. Eight components have been isolated as pure substances, designated as streptovirudins A1, A2, B1, B2, C1, C2, D1, and D2. The streptovirudins are chemically and biologically related to each other and appear to be a new family of antibiotics exhibiting activity against a variety of Gram-positive bacteria, mycobacteria, and various DNA- and RNA-viruses. According to their physico-chemical properties these antibiotics have been classified in series I and II. The streptovirudins of series II (A2, B2, C2, D2) are related to the reported antibiotics tunicamycin, mycospocidin and 24010.