INFLUENCE OF NONIONIC SURFACTANTS ON BACTERIOPHAGE INFECTIONS. I. EFFECT OF TRITON WR-1339 ON T2 COLIPHAGE INFECTION

Rose, Michael J., Jr. (Veterans Administration Hospital, Washington, D.C.), Stephen A. Aron, and Bernard W. Janicki. Influence of nonionic surfactants on bacteriophage infections. I. Effect of Triton WR-1339 on T(2) coliphage infection. J. Bacteriol. 87:933-938. 1964.-Plaques formed by T(2) phage on cultures of Escherichia coli strain B from nutrient broth which contained 0.5% Triton WR-1339 were considerably smaller than those formed on cultures from control broth. Pretreatment of phage particles with Triton did not result in small plaques. Results of population studies showed that treated and control cultures had the same growth rates. Similarly, characteristic physiological reactions of treated cultures were the same as those of the controls. Investigation of the phage growth cycle demonstrated that neither the adsorptive phase nor the latent period was affected by cultivation of the host in Triton. However, the burst size of treated cultures was significantly less than that of control cultures. Analysis of the one-step growth curve data showed that Triton did not inhibit bursting of infected cells. It was concluded that the smaller plaque size was a reflection of a reduced yield of mature virulent phage particles from the Triton-treated cultures.

THE EVALUATION AND MODIFICATION OF A TECHNIQUE FOR COMPARING THE EFFICIENCY OF ANTISEPTICS AGAINST SUBCUTANEOUSLY DEPOSITED BACTERIA IN MICE

An attempt has been made to study the action of antiseptics on artificial streptococcal ;wounds' in mice by a published technique (Martin, 1959). The results were not in agreement with those of Martin and the possible reasons for this are discussed. Suggestions are made for modifying the original method to increase its scope and precision. The production and treatment of Ps. pyocyanea and Kl. aerogenes ;wounds' in mice is described and discussed.

THE IDENTIFICATION AND ISOLATION OF TWO MOUSE-TOXIC PROTEIN COMPONENTS IN EXTRACTS FROM PASTEURELLA PESTIS

The toxin activity of Pasteurella pestis cells, strain "Tjiwidej," was found to be associated with two proteins. Using a disc electrophoresis technique in conjunction with mouse lethality, two toxic proteins were isolated exhibiting intraperitoneal LD₅₀'s of less than 1.0 to 1.5 µg protein. Each produced a single characteristic precipitin band on agar gel diffusion plates. The slower migrating toxin in gel diffusion or disc electrophoresis was designated as toxin A. It was shown to be sensitive to deoxycholate and digitonin, did not accumulate in 5-fluorotryptophan treated cells, and was associated with the membrane fraction of the cell. The faster migrating toxin B, apparently is resistant to surface-active agents, and is not affected by treatment of cells with 5-fluorotryptophan. Toxin B is associated with the soluble or cytoplasmic fraction of the cell. This evidence suggested that each toxin represented a distinctly different molecular species. The possibility is discussed that toxin B is synonymous with the murine toxin previously isolated by paper curtain electrophoresis which revealed only one antigen band in the Oudin precipitin reaction.

IMMUNOGENIC ACTIVITY OF A RIBOSOMAL FRACTION OBTAINED FROM MYCOBACTERIUM TUBERCULOSIS

Youmans, Anne S. (Northwestern University Medical School, Chicago, Ill.), and Guy P. Youmans. Immunogenic activity of a ribosomal fraction obtained from Mycobacterium tuberculosis. J. Bacteriol. 89:1291-1298. 1965.-The highly immunogenic particulate fraction obtained from mechanically ruptured cells of the H37Ra strain of Mycobacterium tuberculosis was suspended and centrifuged at 20,360 x g. The supernatant liquid from this centrifugation was centrifuged at 56,550 x g to remove the larger particles, and the supernatant liquid from this was centrifuged at 144,000 x g to obtain a ribosomal fraction. The sediments from the first two centrifugations were highly immunogenic, but the ribosomal fraction showed only slight capacity to immunize mice. However, when the ribosomal fraction was mixed with Freund's incomplete adjuvant, the immunogenic activity was equivalent to the particulate fraction from which it was prepared. To test the hypothesis that some membranous substance in the particulate fraction was acting as an adjuvant for the smaller particles in the ribosomal fraction, portions of the particulate fraction were treated separately with each of the membrane-disrupting agents, sodium deoxycholate, sodium lauryl sulfate, and 1 m sodium chloride. The treated materials were then centrifuged at 144,000 x g, and the sediments were tested for immunogenicity both with and without the addition of Freund's incomplete adjuvant. Without the adjuvant, the immunizing activities were very weak or absent; with the adjuvant, they were equivalent to that of the particulate fraction from which they were prepared. Other factors which have been found to damage or destroy membranes, such as freezing and thawing, and heat, also significantly decreased the immunogenic activity of the particulate fraction unless it was incorporated into Freund's incomplete adjuvant. The larger particles which sedimented at 56,550 x g were also treated with sodium lauryl sulfate and sodium chloride. Again, immunogenicity was greatly reduced but was fully restored by use of Freund's incomplete adjuvant. The data suggest, then, that the immunizing component of the particulate fraction is a substance (ribosomal?) which sediments at 144,000 x g, but for maximal immunizing activity a labile, possibly membranous, moiety of the mycobacterial cell, which has the properties of an adjuvant, is required.

FINE STRUCTURE OF THE COAT AND NUCLEOID MATERIAL OF FOWLPOX VIRUS

Hyde, James M. (University of Mississippi School of Medicine, Jackson), Lanelle G. Gafford, and Charles C. Randall. Fine structure of the coat and nucleoid material of fowlpox virus. J. Bacteriol. 89:1557-1569. 1965.-Several morphological forms characteristic of the poxvirus group were demonstrated for fowlpox virus with neutral phosphotungstic acid (PTA). Viral particles (purified from viral inclusion bodies) stained with uranyl acetate (UA) and shadowed with platinum were shown to have an external knobby surface not evident with PTA. The external coat of freshly purified viral particles seemed intact, but as the preparation aged, it appeared to unwind, resulting in twisted "rope-like" structures. This process was facilitated by use of 1% trypsin, and three dense fibrils were identified with UA within the partially detached viral coat. Studies with alkaline PTA (pH 9) were interpreted as revealing a complex nucleoid, but solutions above this pH damaged the particles. The morphology of the nucleoid was better depicted in ultrathin sections of whole virus which, when stained with UA, revealed dense coiled threads. Treatment of virus with sodium lauryl sulfate exposed an underlying coat consisting of small subunits approximately 40 A in diameter. Of great interest was the demonstration that the detergent removed strands of deoxyribonucleic acid (DNA) from the virus without destroying the contour of the particle. The origin of the strands was definitely the fine uranophilic, coiled threads of the nucleoid, which probably represent the DNA molecule(s). That the extracted material was largely DNA was proved by digestion with deoxyribonuclease and resistance to ribonuclease and trypsin. These studies illustrate how a variety of electron microscopic techniques may be utilized alone or in combination to reveal hitherto undescribed fine structure of viral particles.

GROWTH OF THIOBACILLUS THIOOXIDANS IN SHAKEN CULTURE

Cook, Thomas M. (Rutgers, The State University, New Brunswick, N.J.). Growth of Thiobacillus thiooxidans in shaken culture. J. Bacteriol. 88:620-623. 1964.-When flasks of sulfur-containing medium were inoculated with Thiobacillus thiooxidans and placed on a shaking machine immediately after inoculation, growth was markedly inhibited. If various wetting agents were provided, or if the ratio of inoculum to sulfur was increased, growth under shaking conditions was possible. Evidence cited shows that the natural wetting agent (or other externally supplied surfactants) is necessary to effect a bacteria-sulfur contact which is stable to shaking conditions.

EFFECT OF TWEEN 80 ON THE GROWTH OF TUBERCLE BACILLI IN AERATED CULTURES

Lyon, Richard H. (Veterans Administration Hospital, Minneapolis, Minn.), Herman C. Lichstein, and Wendell H. Hall. Effect of Tween 80 on the growth of tubercle bacilli in aerated cultures. J. Bacteriol. 86:280-284. 1963.-The effect of Tween 80 (polyoxyethylene sorbitan monooleate), glucose, and glycerol on aerated and stationary growth of Mycobacterium tuberculosis strain H(37)Ra was examined in Dubos liquid medium. Previous studies established that aeration (rotation) of liquid cultures of M. tuberculosis strains H(37)Ra and H(37)Rv caused an inhibition of growth in a medium containing glucose as a source of carbohydrate. The present studies show that Tween 80 exerts a toxic effect on the growth of tubercle bacilli in aerated cultures when glucose is present in the medium as the sole source of carbohydrate, but not when glycerol is included. The role of hydrolytic products of Tween 80, viz. oleic acid and the polyoxyethylene derivative of sorbitol, is discussed. The hypothesis is submitted that glycerol protects against the growth suppression by aeration because it reduces the concentration of free fatty acids in the medium to subinhibitory levels.

EFFECT OF DETERGENT ON ELECTRICAL PROPERTIES OF SQUID AXON MEMBRANE

The effects of detergents on squid giant axon action and resting potentials as well as membrane conductances in the voltage clamp have been studied. Anionic detergents (sodium lauryl sulfate, 0.1 to 1.0 mM; dimethyl benzene sulfonate, 1 to 20 mM, pH 7.6) cause a temporary increase and a later decrease of action potential height and the value of the resting potential. Cationic detergent (cetyl trimethyl ammonium chloride, 6 x 10^-5M or more, pH 7.6) generally brings about immediate and irreversible decreases in the action and resting potentials. Non-ionic detergent (tween 80, 0.1 M, pH 7.6) causes a slight reversible reduction of action potential height without affecting the value of the resting potential. Both anionic and cationic detergents generally decrease the sodium and potassium conductances irreversibly. The effect of non-ionic detergent is to decrease the sodium conductance reversibly, leaving the potassium conductance almost unchanged.