Examination of L-transformation in salmonella by electron and laser inference microscopy

The existence of bacteria without a cell wall was found to be a quite specific and widespread phenomenon, which could not be explained in terms of classical microbiology. The L-transformation of bacteria makes difficult determining the athogens and leads to the false-negative conclusions of biological assays because of L-forms are in uncultivated state. The L-transformation caused by abiotic (tetracycline) and biotic ( Bacillus subtilis) factors as well as reversion of L-forms were studied in Salmonella enterica serovar typhimurium population using transmission electron and laser interference microscopy. The morphological parameters of L-forms, which are able to reverse in an initial state, were revealed. Development of super-resolution optical microscopy methods makes possible conducting real-time studies of L-transformation with the living non-modified bacteria. The 3D phase portraits obtained using laser interference microscope MIM-321 make it possible to identify L-forms clearly as well as to determine its basic morphological parameters (diameter, perimeter, height, surface, volume). The ring shaped structures (supposedly identified as DNA) were detected using the modern algorithms of signal processing. It is important to note that heteromorphism including all stages of L-transformation is inherent for all pathogenic and conditionally pathogenic bacteria (both in normal conditions and under biotic and abiotic factors treatment) to provide population survival. The study of L-transformation is extremely important for understanding of potentially infectious agent’s reservoirs as well as chronic disease relapses in vivo.