CHEMICALLY DEFINED, SYNTHETIC MEDIA FOR SPORULATION AND FOR GERMINATION AND GROWTH OF BACILLUS SUBTILIS

Donnellan, J. Edward, Jr. (U.S. Army Natick Laboratories, Natick, Mass.), Ella H. Nags, and Hillel S. Levinson. Chemically defined, synthetic media for sporulation and for germination and growth of Bacillus subtilis. J. Bacteriol. 87:332-336. 1964.-From 90 to 130 mg (dry weight) of spores (about 1% dark forms) were obtained (per liter) from a chemically defined, synthetic medium, with a two-phase (polyethylene glycol-potassium phosphate) harvest procedure. Optimal sporulation occurred when glucose and glutamic acid were at a concentration of 10 mm in the medium. Ca(++) and Mn(++) were required for sporulation. Heat resistance, dipicolinic acid content, and properties of germination and postgerminative development of spores grown in different concentrations of Ca(++) were investigated. Heat shock did not increase germination of spores derived from the synthetic medium. A synthetic medium, in which spore germination, emergence, and first cell division approached synchrony, was devised.

EXTRACELLULAR RIBONUCLEASE FORMATION IN BACILLUS SUBTILIS AND ITS STIMULATION BY ACTINOMYCIN D

1. Extracellular ribonuclease is produced linearly for at least 3hr. by washed post-logarithmic-phase cells of Bacillus subtilis suspended in a medium containing maltose (1%) and casein hydrolysate (0.5%). 2. Low concentrations of actinomycin D (less than 2mug./ml.) stimulate ribonuclease formation, the maximum effect being observed with a concentration of 1mug./ml. Concentrations greater than 2mug./ml. are inhibitory. There is no parallel stimulation of alpha-amylase formed under the same conditions, and [(14)C]uracil incorporation into a perchloric acid-insoluble form is inhibited. 3. The actinomycin D-induced stimulation is not due to the presence of an activator, nor is the inhibition due to the release of an inhibitor by the cells. The effect is on the amount of ribonuclease produced in the medium. 4. Extracellular ribonuclease formation is partially inhibited by anaerobiosis, 2,4-dinitrophenol, sodium azide and by chloramphenicol and puromycin. 5. High concentrations of antibiotic do not completely inhibit ribonuclease formation, but a basal amount of enzyme representing 20min. synthesis in an uninhibited system is always produced. This ;antibiotic-insensitive' enzyme could possibly represent preformed enzyme ;in the pipe-line' en route to secretion. 6. The stimulated appearance of ribonuclease in the presence of 1mug. of actinomycin D/ml. is shown to be dependent on enzyme synthesis. The mechanism of this effect is discussed.

BIOSYNTHETIC LATENCY IN EARLY STAGES OF DEOXYRIBONUCLEIC ACIDTRANSFORMATION IN BACILLUS SUBTILIS

Nester, E. W. (University of Washington, Seattle) and B. A. D. Stocker. Biosynthetic latency in early stages of deoxyribonucleic acid transformation in Bacillus subtilis. J. Bacteriol. 86:785-796. 1963-In the Bacillus subtilis deoxyribonucleic acid (DNA) transformation system, transformants do not increase in number for 3 to 5 hr after the addition of DNA. During most of this period, the transformants are resistant to the bactericidal action of penicillin under conditions which result in the killing of over 90% of the recipient population. This lag in growth and nonmultiplication of the transformants (inferred from penicillin resistance) is also reflected in a lag in the synthesis of an enzyme specified by the donor DNA. Thus, when a cell population deficient in the enzyme tryptophan synthetase is transformed to tryptophan independence, activity of this enzyme cannot be detected in whole cells until 3 to 4 hr after the cells have been exposed to the DNA. Recombination between donor and recipient DNA occurs long before this. Even 30 min after exposure of a competent population of try(2) (-)his(2) (+) cells to try(2) (+)his(2) (-) DNA, 20% of the total try(2) (+) activity found in re-extracted DNA exists as recombinant DNA, try(2) (+)his(2) (+). This value, the maximal linkage obtained, remains constant during incubation of the DNA-treated culture for an additional 5 hr. In addition to the heterogeneous response of a DNA-treated competent culture to penicillin killing, the recipient culture appears to be heterogeneous in ability to undergo transformation. Thus, the frequency of joint transformation of two unlinked markers is much higher than would be expected on the basis of the random coincidence of more than one DNA molecule entering the same cell in a uniformly competent recipient population. A possible relationship between these two aspects of heterogeneity of a DNA-treated recipient population is discussed.

SINGLE-STAGE IMPACTION DEVICE FOR PARTICLE SIZING BIOLOGICAL AEROSOLS

A single-stage impactor device, capable of fractionating a bacterial aerosol into its component mass size classes while preserving the viability of sensitive vegetative cells against the deleterious effects of desiccation and impaction, is described. Among the valuable features of the impactor are its negligible wall loss, ease of fabrication and use, and relative inexpensiveness.

TRANSFORMATION OF BACILLUS LICHENIFORMIS

Gwinn, Darrel D. (Oregon State University, Corvallis), and Curtis B. Thorne. Transformation of Bacillus licheniformis. J. Bacteriol. 87:519-526. 1964.-When a series of 28 auxotrophic mutants of Bacillus licheniformis were screened for transformation, only three of them, M28 (glycine(-)), M30 (uncharacterized), and M33 (purine(-)), produced a detectable number of transformants. The screening method consisted of spreading auxotrophic cells and deoxyribonucleic acid (DNA) from the prototrophic strain 9945A on minimal agar plates and observing the plates for development of prototrophic colonies. M28 transformed at a higher frequency than did the two other mutants, and it was studied in greater detail. Although up to 20% of the recipient cells spread on the plates in the presence of DNA gave rise to prototrophic colonies over a period of 72 hr, only about 10(-3)% of the cells produced transformants when they were incubated with DNA in liquid suspension for 1 hr. The most competent cultures of many tested were those grown on a shaker for 22 hr in a medium composed of nutrient broth, salts, and glycerol. When mutations resulting in requirements for histidine, leucine, serine, and trytophan were introduced singly into the glycine mutant, transformants for the leucine, serine, and histidine markers could be obtained at will, but transformants for the tryptophan marker were not detected even though all four of the double mutants could be transformed to glycine independence.

USE OF CALCIUM DIPICOLINATE FOR ENUMERATION OF TOTAL VIABLE ENDOSPORE POPULATIONS WITHOUT HEAT ACTIVATION

A method, based on germination with 50 mm CaCl(2) and 40 mm sodium dipicolinate (Na(2)DPA), was developed for the determination of total viable counts of bacterial spores requiring heat activation. Incorporation of these germinating agents into Tryptone Glucose Extract Agar permitted plate-count enumeration of essentially 100% of Bacillus subtilis strain 5230 spores without a heat treatment. Other spore suspensions were surveyed for their response to CaCl(2) and Na(2)DPA, and for the subsequent removal of the heat-activation requirement for enumeration of maximal populations.

BIOSYNTHESIS OF MYCOBACILLIN, A NEW ANTIFUNGAL PEPTIDE. I. ROLE OF NUCLEIC ACID

Banerjee, Arun B. (University of Calcutta, Calcutta, India), and S. K. Bose. Biosynthesis of mycobacillin, a new antifungal peptide. I. Role of nucleic acid. J. Bacteriol. 87:1397-1401. 1964.-The biosynthesis of mycobacillin, a cyclic polypeptide antifungal antibiotic, was studied in relation to the effect of chloramphenicol, 6-azathymine, and 5-bromouracil on the process. It was found that chloramphenicol inhibits both mycobacillin synthesis and growth, whereas nucleic acid base analogues inhibit only growth and nucleic acid synthesis but not mycobacillin formation. A change in the concentration of labeled aspartic acid in the general metabolic pool led to a corresponding change in the specific activity of aspartic acid isolated from different peptide fragments of the mycobacillin molecule, suggesting that mycobacillin synthesis occurs by way of linear addition of amino acid to the peptide chain.

POLYOMA VIRUS: PRODUCTION IN BACILLUS SUBTILIS

Particles of complete polyoma virus are produced in competent Bacillus subtilis incubated with DNA isolated from purified, conventionally grown polyoma virus. The virus grown in B. subtilis is biologically identical to polyoma virus produced by animal cells. Quantitative parameters of the system have been established, and fluctuation tests indicate that viral replication occurs within the infected bacteria.