Non-Heating Alternating Magnetic Field Nanomechanical Stimulation of Biomolecule Structures via Magnetic Nanoparticles as the Basis for Future Low-Toxic Biomedical Applications.

The review discusses the theoretical, experimental and toxicological aspects of the prospective biomedical application of functionalized magnetic nanoparticles (MNPs) activated by a low frequency non-heating alternating magnetic field (AMF). In this approach, known as nano-magnetomechanical activation (NMMA), the MNPs are used as mediators that localize and apply force to such target biomolecular structures as enzyme molecules, transport vesicles, cell organelles, etc., without significant heating. It is shown that NMMA can become a biophysical platform for a family of therapy methods including the addressed delivery and controlled release of therapeutic agents from transport nanomodules, as well as selective molecular nanoscale localized drugless nanomechanical impacts. It is characterized by low system biochemical and electromagnetic toxicity. A technique of 3D scanning of the NMMA region with the size of several mm to several cm over object internals has been described.

Peptidoglycan degrading activity of the broad-range Salmonella bacteriophage S-394 recombinant endolysin.

The use of bacteriophage endolysins as specific antibacterial agents is a prospective strategy to treat bacterial infections caused by antibiotic-resistant pathogens. In case of Gram-negative species this strategy has limited applications since outer membrane shields the enzyme target and prevents bacteria lysis. We aimed to obtain and characterize the endolysin of the newly discovered anti-Salmonella bacteriophage S-394 (Lys394) and to choose an appropriate permeabilizing agent to disrupt Escherichia coli cells suspended in buffer solution and grown on agar surface. Lys394 synthesized in E. coli C41(DE3) was obtained as an electrophoretically homogenous protein. The protein of 18 kDa molecular weight shows high muralytic activity against various genera of chloroform treated Gram-negatives. Maximum of enzyme activity was observed at pH 8.5 and low ionic strength. In silico analysis of amino acid sequence identified Lys394 as an endopeptidase. Various outer membrane permeabilizers were analyzed in combination with Lys394 to degrade laboratory strain of E. coli CR63. Permeabilizing activity was evaluated using a periplasmic ß-lactamase leakage test with untreated E. coli cells as a substrate. The highest rate of planktonic E. coli lysis was reached for Lys394 applied together with 25 µg/ml of poly-l-arginine with molecular weight distribution from 5 to 15 kDa or 20 µg/ml PGLa peptide. Lawn E. coli colony forming ability was decreased by 4 orders of magnitude after 30 min treatment with 25 µg of Lys394, 1 mM EDTA and 50 µg/ml of PGLa peptide at a room temperature.