PubMed · 13353545
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G RAHNFELD. 1956. [Involutional forms and L-forms of Streptococci].. https://pubmed.ncbi.nlm.nih.gov/13353545/
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Tinctural specificity was studied for various mycobacterial species (M. tuberculosis Erdman TMC 107, M. tuberculosis Academia, M. Bovis Bovinus-8, M. Bovis BCG Russian, M. Avium Avium-53) subjected to staining according to Ziehl-Neelsen, Boy (fluorescent staining), Gram and Romanovsky-Gimze. The cultures were studied on Pavlovsky's continuous medium under natural ageing. The authors tested adequacy of diverse bacterioscopic methods for registration of all the cells in the mycobacterial population. Mycobacterial morphological and tinctural features are shown to be dependent on the culture duration and species. Non-conventional Gram's and Romanovsky-Gimze techniques were able to identify L-form granular balls and non-acid-fast coccus-like forms. The presence and the number of mycobacterial changed forms are species-specific and related to the culture duration.
No major differences have been found in series of Staphylococcus aureus strains which reverted from 'L'-phase, either by pyrolysis mass spectrometry or by phage-typing or sensitivity testing. In 'L'-phase they have been subcultured for a long time or transformed/reverted many times into/from 'L'-phase. Plasmids were lost during transformations/reversions, but there was some difference between the tetracycline-connected plasmids on the one hand and the erythromycin-connected ones on the other.
Stable L-forms of Salmonella typhi and Listeria monocytogenes were produced using penicillin (4500 units/ml) as inducer, and sucrose, normal horse serum and Mg++ as stabilizers. Stable L-forms were produced after 100 and 56 passages, then adapted to grow and multiply in a medium free of inducer and stabilizers so that they did not revert to parental forms even after 12 continuous passages.