Action of 6-Aminopenicillanic Acid on Gram-negative Bacteria

NU.4753 December 3, 1960 NATURE 875 cause of the slowness in its growth, is conspicuous, alt,hough the efficiency of the assimilatory process, as expressed by the carbon dioxide/hydrogen ratio, is not inferior. For the purpose of comparison, typical data in tbis connexion are summarized in Table 3 together with our own results. The slow rate found in the present case may partly originate from the eircumstance that we had to use cells taken from old cultures, often several weeks old, in order to secure sufficient amounts of the organism for the test. We wish to acknowledge here the continuous interest of Prof. H. Tamiya, University of Tokyo, during this work, which was supported in part by a research grant from the Ministry of Education. RYUZI KANAI SHIGETOH MIYACHI ATusI TAKAMIYA Department of Biophysics and Biochemistry, and Institute of Applied Microbiology, University of Tokyo. It can be seen that sodium 6-aminopenicillanate in concentrations approximately twice those of sodium benzylpenicillin induced spheroplast formation. In lower concentrations, bizarre morphological variants were obtained. The spheroplasts underwent lysis on dilution of the medium with water. Batchelor et al.' report that 6-aminopenicillanic acid possesses definite antibacterial properties, but of a much lower order than benzylpenicillin. It would appear that the presence of the acyl side-chain on the primary amine is not essential for spheroplast formation. Quantitative differences may be due to factors involving access to the site of action. We thank Drs. J. Farquharson and E. T. Knudsen, of Beecham Research Laboratories, for a generous gift of 6-aminopenicillanic acid and 6-(rx-phenoxypropionamido )penicillanic acid. Takamlya, A., and Tubaki, K., Archiv Mikrobiol., 25, 58 (1956). 'Schatz, A., and BoveU, jun., C., J. Bact., 63, 87 (1952). • Schatz, A., J. Gen. Microbiol., 6, 329 (1952). • Packer, L., and Vishniac, W., J. Bact., 7G, 216 (1955). 'McFadden, B. A., and Atkinson, D. E., Arch. Biochem. Biophys. 66, 16 (1957). • Orgel, G., Dewar, N. E., and Koffler, H., Biochim. Biophys. Acta 21, 409 (1956). 1 1 W. B. HUGO A. D. RUSSELL The University, Nottingham. Lederberg, J., Proc. D .S. Nat. Acad. Sci., 42, 574 (1956); J. Bact., 73,144 (1957). Liebermaster, K., and Kellenberger, E., Z. Naturjorsch., llb, 200 (1956). Hahn, F. E., and Ciak, J., Science, 125, 119 (1957). Lark, K. G., Canad. J. Microbiol., 4, 165 (1958). Hugo, W. B., J. Pharm. Pharmacal., 10, 590 (1958). • Batchelor, F. R., Doyle, F. P., Nayler, J. H. C., and Rolinson, G. N, Nature, 183, 257 (1959). VIROLOGY Action of 6-Aminopenicillanic Acid on Gram-negative Bacteria THERE is abundant evidence to support the theory that at least one way in which penicillin exerts its antibacterial effect is to prevent the synthesis, during cell division, of a rigid component of the cell wall. If this action takes place in normal culture medium, the result is lysis; if in a hypertonic environment, the cell changes into a spherical body or spheroplast'. We have found that the parent amine, 6-aminopenicillanic acid', from which the natural penicillins may be considered to be derived by acylation, induces morphological changes similar to those produced by benzylpenicillin, 6 -(rx-phenoxypropionamido )penicillanic acid (,Broxil'), and phenoxymethylpenicillin (penicillin V). In our experiments, 0·15 m!. of a 17-hr. culture of the organism, grown on a rotator at 37° C., was added to 10 ml. of the following medium, containing per litre: sodium chloride 5 gm., 'Lab. Lemco' (Oxoid) 5 gm., peptone 10 gm., sucrose 114 gm., crystalline magnesium sulphate 2·5 gm. The sodium salt of 6-aminopenicillanic acid was added to give the desired final concentration. Examination by interference microscopy after incubation for 4-5 hr. at 37° C. gave the results shown in Table 1. Table L CONCENTRATIONS OF SODIUM BENZYLPENICILLIN AND SODIU~1 6-AMINOPENlCILLANATE TO IN PUCE SPHEROPLAST FORMATION IN CERTAIN GRA'I-NEGATIVE BACTERU ,------ --------7' E. coli (formerly N.C.T.C. 5934) Cloaca cloacae (N.C.T.C. 8155) E. coli (K12) Ps_ pyocyanea (N.C.T.C. 7244) Serratia marcescens P"oteus vllluaris (N.C.T.C. 7052) Sodiunt benzylpenicillin (I'mole/ml.) Sodium 6-aminopenicillanate (I'm"le/ml.) 0'167 0·167 1·67 0·42 1·67 1'67 0'68-1 '7 0·34 3'4 0·84 1'7-3 ·4 1'7-3 ·4 Serological Detection of a Virus in Cherry Trees with a Leaf Roll Disease LEAF roll virus disease of sweet cherry (Prunus avium)',' has been identified (by graft-transmission to indicator plants) in eight orchards in Kent and one in Worcestershire. Six of these outbreaks have been investigated further, and in each of them the same virus was isolated from infected trees. When buds or young leaves were macerated in 0 ·05 M phosphate buffer (pH 7 ·8) or 0·01 M sodium diethyl-dithiocarbamate solutions and rubbed on to the leaves of young herbaceous plants, chlorotic and necrotic spots, rings and lines developed on the leaves of tobacco (var. White Burley), while Chenopodium arru:tranticolor plants were stunted, with mottled and distorted leaves. The virus was also transmitted by sap inoculation from tobacco to Prunus avium and P. pennsylvanica seedlings, and from Prunus avium to P. pennsylvanica. An antiserum was prepared by intravenous injections into a rabbit of virus preparations precipitated from the infective tobacco sap by ammonium sulphate. Precipitation tests were made in a gel containing 0·7 per cent 'Ionagar' No.2, 0·9 per cent sodium chloride and 0 ·02 per cent sodium azide. This medium was run into Petri dishes to a thickness of 3 mm., and holes cut in the gel with a small cork borer to receive diluted antiserum or antigen. Single precipitation lines formed between holes filled with antiserum and those with undiluted sap from Chenopodium plants infected with this virus. No precipitation lines formed with sap from healthy Chenopodium plants or from plants infected with Arabis mosaic and tomato black ring viruses. Specific precipitation lines were formed when sap from buds or young leaves from infected cherry trees was used as the antigen; the sap was antigenic © 1960 Nature Publishing Group  (...truncated)