[Relationship between culture and conditions, the qualitative composition of a culture of Bacillus brevis and its formation of gramicidin C]

Qualitative composition of the population of Bacillus brevis was found to depend on growth conditions. Under optimum aeration conditions for growth of the culture and biosynthesis of gramicidin C, the population was polymorphous and contained cells and spores of different age. No spores and prospores were found in the culture in conditions of weak and strong aeration. The population consisted only of young, intensively coloured cells with homogeneous or weakly differentiated content in conditions of strong aeration. Cells with the differentiated protoplasm containing large, distinctly seen vacuoles were found in conditions of weak aeration. Gramicidin C was synthesized by young cells with basophilic homogeneous or weakly differentiated protoplasm.

Isolation of a new peptide antibiotic complex, B-43 (studies on antibiotics from the genus Bacillus. XV)

A new peptide antibiotic complex B-43, active against Gram-positive and Gram-negative bacteria, was isolated from a strain of Bacillus circulans. This antibiotic contains aspartic acid, valine, isoleucine, leucine, phenylalanine and 2,4-diaminobutyric acid. It seems to be related to polypeptin and antibiotic complex 4205, but differs in that it contains aspartic acid residue.

Isolation of a new peptide antibiotic, 339-29 (studies on antibiotics from the genus Bacillus. XIV)

A new antibiotic named 339-29, active against Gram-positive bacteria was isolated from a strain of Bacillys pumilus. The hydrochloride is soluble in water and aqueous alcohols. The antibiotic is a basic peptide containing valine (3), isoleucine (1), Leucine (2), tyrosine (1), lysine (3) and a fatty acid.

Isolation of a new antibiotic 333-25, related to antibiotic EM 49. (Studies on antibiotics from the genus Bacillus. XI)

A new antibiotic, 333-25, active against Gram-positive and Gram-negative bacteria, was isolated from the culture broth of Bacillus circulans 333-25. The antibiotic is a basic acylpeptide containing 2,4-diaminobutyric acid (5), leucine (2), phenylalanine (1) and a fatty acid. It is closely related to antibiotic EM 49, but can be differentiated by chromatographic behaviour.

Estimates of the porosity of Bacillus licheniformis and Bacillus subtilis cell walls

The maximum porosity of Bacillus subtilis and Bacillus licheniformis cell walls was estimated by two independent and relatively simple methods. Peptidoglycan was isolated from Bacillus subtilis cell wall preparations and used as an insoluble support for exclusion chromatography of dextrans of known average molecular size. In an alternative approach the leakage of radioactively labelled proteins from Bacillus licheniformis cells incubated in butanol-saline mixtures was measured and their size estimated by exclusion chromatography on Sephadex G-100. Under these conditions the permeability barrier of the cytoplasmic membrane was destroyed with preservation of the structural integrity of the outer cell wall. The apparent exclusion threshold of the cell wall of either organism as determined by these means corresponded to molecules with a diffusional radius of not more than 2.5 nm.

Determination of exotoxin in Bacillus thuringiensis cells

The presence of exotoxin in Bacillus thuringiensis was demonstrated and its quantity in the cells determined. The concentration of exotoxin in the producing microorganism is approximately half the concentration of ATP. Exotoxin is produced at such a rate that the cell excretes 1/5 to 1/4 of its exotoxin content into the medium per minute.

[Various properties of a stable variant of Bacillus thuringiensis (Berliner) resistant to aflatoxin B1]

A new aflatoxin B1 resistant strain of Bacillus thuringiensis (Berliner), designated "variant stable," was isolated in the presence of a mycotoxin lethal dose. The enzymatic and physiological properties of this slow-growing clone are in all respects similar to those of the original strain (in particular its resistance to a variety of antibiotic, antimitotic, or carcinogenous agents). Besides their radically opposite behavior with respect to aflatoxin B1, the colonies of these two strains differ only by their size and aspect: marginal and surface organization.[Journal translation]

Reversal of filament formation in the psychrophile Bacillus insolitus

When filamentous cells of Bacillus insolitus, formed by incubation at 30C, were incubated at 20C, a resumption of cross-wall formation occurred. Reversal of the inability to divide did not occur when de novo protein synthesis was prevented by chloramphenicol, or when D-cycloserine, vancomycin, or penicillin was present. Resumption of septation did take place in the presence of nalidixic acid.

Structure and assembly of bacterial surface layers composed of regular arrays of subunits

Regular arrays of subunits are observed on the surfaces of many bacteria, and the structure and function of such an array are being examined in a study of the Gram-negative bacterium Acinetobacter strain MJT/F5/199A. The subunits are on the surface of the outer membrane and are visible in electron micrographs of freeze-etched intact cells and of negatively stained preparations of isolated cell walls and outer membranes. The surface subunits can be detached from the membrane by various treatments and will then reassemble spontaneously to form the same regular pattern as that seen on the intact bacterium. The results of studies of the properties of the self-assembly system are described and its relevance to the formation of surface layers composed of regular arrays of subunits in intact bacteria discussed.

Increased radiation resistance of vegetative Bacillus pumilus

A 4.5-fold increase in vegetative cell radiation resistance of Bacillus pumilus E601, the internationally recognized biological standard for irradiation sterilization, was obtained by the repeated passage of resistant survivors through successive sublethal doses of (60)Co irradiation. This increase in resistance was accompanied by a corresponding increase in spore resistance through the seventh irradiation passage. By the fifteenth passage, the ability for spore formation was lost. Other effects noted by the successive irradiation dosages included loss of motility and pellicle formation, and changes in the Gram reaction, cell morphology, and colonial morphology. Increased resistance was also accompanied by an increased nutritional requirement for specific amino acids. Radiation resistance was not transferred from vegetative cells to spores.