Time-reversal violating rotation of polarization plane of light in gas placed in electric field

Rotation of polarization plane of light in gas placed in electric field is considered. Different factors causing this phenomenon are investigated. Angle of polarization plane rotation for transition 6S_{1/2} - 7S_{1/2} in cesium (lambda=539 nm) is estimated. The possibility to observe this effect experimentally is discussed.Comment: 10 pages, Late

Laser induced breakdown of the magnetic field reversal symmetry in the propagation of unpolarized light

We show how a medium, under the influece of a coherent control field which is resonant or close to resonance to an appropriate atomic transition, can lead to very strong asymmetries in the propagation of unpolarized light when the direction of the magnetic field is reversed. We show how EIT can be used to mimic effects occuring in natural systems and that EIT can produce very large asymmetries as we use electric dipole allowed transitions. Using density matrix calculations we present results for the breakdown of the magnetic field reversal symmetry for two different atomic configurations.Comment: RevTex, 6 pages, 10 figures, Two Column format, submitted to Phys. Rev.

Adaptation of Mycoplasmas to Antimicrobial Peptides: Development of Melittin Resistance in Acholeplasma laidlawii Is Associated with Changes in Genomic and Proteomic Profiles and in Virulence

© 2020, Pleiades Publishing, Ltd. Abstract: For the first time it is shown that the development of resistance to melittin in Acholeplasma laidlawii, a mycoplasma that is widely spread in nature and that is the main contaminant of cell cultures and vaccines, is associated with significant changes in the genomic profile, in cellular and vesicular proteomes, as well as in virulence

Antimicrobial drug resistance mechanisms among Mollicutes

Representatives of the Mollicutes class are the smallest, wall-less bacteria capable of independent reproduction. They are widespread in nature, most are commensals, and some are pathogens of humans, animals and plants. They are also the main contaminants of cell cultures and vaccine preparations. Despite limited biosynthetic capabilities, they are highly adaptable and capable of surviving under various stress and extreme conditions, including antimicrobial selective pressure. This review describes current understanding of antibiotic resistance (ABR) mechanisms in Mollicutes. Protective mechanisms in these bacteria include point mutations, which may include non-target genes, and unique gene exchange mechanisms, contributing to transfer of ABR genes. Better understanding of the mechanisms of emergence and dissemination of ABR in Mollicutes is crucial to control these hypermutable bacteria and prevent the occurrence of highly ABR strains

Adaptation of Mycoplasmas to Fluoroquinolones: Modulation of Proteome and Genotoxicity of Extracellular Vesicles of Acholeplasma laidlawii

The paper is devoted to the comparative analysis of proteomic profiles and genotoxicity of extracellular vesicles produced by cells that differ in sensitivity to ciprofloxacin of Acholeplasma laidlawii strains – the mycoplasma, being a causative agent of mycoplasmoses of plants and animals, as well as the main contaminant of cell cultures. The relevance of the study is determined by the fact that extracellular vesicles – nanostructures surrounded by a membrane mediating intercellular communication and pathogenesis in bacteria are involved in adaptation of A. laidlawii to antimicrobials and present a new type of infects, the study of which is associated with the prospects of determining the mechanisms of host-parasite systems and solution of problems of pathogen control. The present study has been performed with a view of elucidation of the proteome profile features and assessment of the genotoxicity of extracellular vesicles of A. laidlawii in the development of resistance of the mycoplasma to ciprofloxacin – a drug of fluoroquinolone group which is widely used for inhibiting mycoplasmas. To achieve this goal, we have used the standard microbiological methods, as well as the modern physical and chemical methods, including proteomic profiling with help of 1D-LC-ESI-MS/MS, PCR, automatic scanning, and karyotyping system for assessment of the genotoxicity of vesicles. It has been shown that a significant part of vesicular proteome of A. laidlawii strains with differential sensitivity to ciprofloxacin represents the bacterial virulence factors, as well as that the vesicles of all strains exhibit genotoxicity to lymphocytes of human peripheral blood in vitro. The most important of these results is the fact that the development of resistance of A. laidlawii to ciprofloxacin is accompanied by a significant modulation of vesicular proteome and the increase of mitotoxicity to eukaryotic cells. The obtained data are essential for fundamental research and applied works in the control system of socially significant infections, contaminations of cell cultures and vaccines. The results of the study provide fundamentally new notions about the processes of adaptation of A. laidlawii to antimicrobial drugs and pathogenicity of extracellular vesicles of mycoplasma, as well as suggest the necessity for correction of the control system of mycoplasmas with a view of bacterial vesicles as a new type of infects

Adaptation to Antimicrobials and Pathogenicity in Mycoplasmas: Development of Ciprofloxacin-Resistance and Evolution of Virulence in Acholeplasma laidlawii

Abstract: For the first time it was shown that the development of resistance to ciprofloxacin in vitro in Acholeplasma laidlawii, a mycoplasma which is widely spread in nature and which is the main contaminant of cell cultures and vaccines, is associated with diverse pathways of virulence evolution: virulome and virulence differ significantly between ciprofloxacin-resistant strains, including those with the same level of antimicrobial resistance