H37 Ra Research Articles

Inhibition by isoniazid of synthesis of mycolic acids in Mycobacterium tuberculosis.

SUMMARY Exposure of growing Mycobacterium tuberculosis bcg to 1 µ g. isoniazid/ml. inhibited the incorporation of 14C from [U-14C] and [2-14C]glycerol and [1-14C]- glutamate into its walls by about 50 % over 12 h. because 14C incorporation into the mycolic acids of the walls was prevented. Isoniazid, 0·5 µ g. / ml. with M. tuberculosis bcg or 0·1 µ g./ml. with M. tuberculosis H37 Ra, inhibited incorporation of 14C from [U-14C] glycerol into total mycolic acids by about 90 % over 6 h., indicating that inhibition began within 1 h. of the addition of the drug. There was no effect on mycolic acid synthesis in an isoniazid- resistant strain of M. tuberculosis bcg. The primary inhibitory action of isoniazid in sensitive mycobacteria is probably on mycolic acid synthesis, and this leads to formation of defective boundary layers of the bacteria.

Phosphatide antigens of mycobacteria.

SummaryThe nature of phosphatide antigens of 5 species of mycobacteria has been investigated by the kaolin-agglutination technique of Takahashi using serum from tuberculous patients as antibody source. The phosphatide antigens are present in virulent (H37 Rv, M. avium), avirulent (H37 Ra) and saprophyte (M. 607, M. phlei) strains of mycobacteria. The phosphatide antigens have been purified by silicic acid column and paper chromatography and identified as phosphatidyl inositomannosides.

投酸性菌の物質代謝に関する研究

In order to study the enzymatic properties of human type tubercle bacilli, H37 Rv, H37 Ra and BCG, and avian type bacilli, Takeo's strain, Myc. ATCC 607 and Myc. phlei, the auther prepared the soluble fraction and particulate fraction of these cells by means of ultracentrifuge frnm the ground cells that were cultured in Sauton's media. Using the fractions thus obtained, the author observede nzyme activities of these fractions. And then, the author picked out the soluble fraction of H37 Ra; dialyzed it and studied the dehydrogenase activity of the dialyzed soluble fraction for lactate and malate with the addition of Cofactor by means of Thunberg's methylen blue reduction method. The following results were obtained.1) It was observed that the enzyme activities of two fractions, soluble and particulate, were distinctly different in any organisms.2) It could be comfirmed that the specilic enzyme activity of each fraction for ehe substrates and the intensities of that activities were varied as the strains.3) The dehydrogenase activity of the dialyzed soluble fraction of H37 Ra for lactate was raised by the addition of CoI. And riboflavin could substitute for CoI.4) The more increased dehydrogenase activity for malate was observed by the simultaneous addition of GoI and riboflavin to the dialyzed soluble fraction of H37 Ra compaired with the single addition of CoI to that fraction. However riboflavin failed to replace the role of CoI.

抗酸性菌の物質代謝に関する研究

Using the same procedure and organisms as in the Part I, the author prepared the soluble fraction and the particulate fraction, and carried out further enzymatic study of these fractions by means of Warburg's manometer techinipue. The following results were obtained.1) The soluble fraction of H37 Rv and H37 Ra could oxidize lactate and other substrates fairly successfnlly; but on the other hand, the particulate fractions of that coule oxidize lactate and succinate specifically and failed to oxidize the other substrates. And this fact was also noticed in the case of the particulate fraction of BCG.2) In the case of Takeo's strain one of the avian type bacilli, the enzyme system that oxidise malate was found merely in the particulate fraction.3) It could be observed that the soluble fraction of Myc. ATCC 607 showed intense endogeneous respiration, and the particulate fraction of the organism could oxidize fumarate and malate specifically.4) The soluble fraction of Myc. phlei could oxidize lactate successfully, but oxideze the other substrates not so satisfactorily. And in the case of the particulate fraction, it could oxidize any of lactate, succinate or malate, but, in a small extent.

Changes in morphology of an avirulent strain of Mycobacterium tuberculosis under the influence of nonionic surface-active agents.

Summary: When the avirulent strain of Mycobacterium tuberculosis H37 Ra was repeatedly subcultured in a liquid medium containing low concentrations of ‘Triton A20’ or other chemically similar non-ionic surface-active polyoxyethylene ethers, the morphology changed from the amorphous growth pattern characteristic of avirulent tubercle bacilli to the formation of microscopic ‘cords’ similar to those shown by virulent strains such as H37Rv. Once developed, the cord-forming property of H37 Ra persisted when cultures were transferred to liquid medium devoid of surface-active agent, even when such transfer was made after passage through mice; after further subcultures, however, a tendency to reversion was apparent. No difference in virulence was detected between cord-forming H37 Ra and the unmodified strain when tested in mice. Previous work had indicated that a lower member of the polyoxyethylene ether series, the dimer ‘D4’, inhibited amorphous-growing avirulent tubercle bacilli, including H37 Ra, but not the growth of naturally cord-forming strains, exemplified by the virulent H37 Rv and attenuated strains derived from it. The growth of cord-forming avirulent organisms, developed from H37 Ra in the present experiments, was also found to be relatively unaffected by D4.

The inhibition of growth of avirulent strains of Mycobacterium tuberculosis by a surface-active polyoxyethylene ether.

Examination of the action of a series of surface-active polyoxyethylene ethers on the growth of the avirulent strain of Mycobacterium tuberculosis, H37 Ra, showed that one member, the ether of 2,2′-dihydroxy-5, 5′-di-tert-octyldiphenyl-methane (D4), inhibited this strain but not the virulent variant H37 Rv. This type of differential inhibition has been observed with a commercial surface-active mixture, ‘Triton A20’ (Dubos & Middlebrook, 1948). Lengthening of the polyoxyethylene chains of D4 led to loss of its inhibitory property. Both D4 and ‘Triton A20’ could induce resistance in H37 Ra, and cross-resistance to D4 of a strain resistant to ‘Triton A20’ was observed; this cross-resistance suggested that a compound closely related to D4 was the active constituent of ‘Triton A20’. The resistant strains grew in a microscopically amorphous pattern, like their parent strain. The growth of four other avirulent strains of tubercle bacilli was inhibited, like that of H37 Ra, by D4, while two slightly virulent strains grew freely in this detergent, like H37 Rv. One factor common to the strains naturally insusceptible to D4, but absent from those inhibited, is the ability to produce some degree of microscopic ‘cord’ pattern, and this property may have some connexion with the cause of the differential inhibition by D4. Surface activity also probably plays a part.