6 research outputs found

    Spread of Correlations in Strongly Disordered Lattice Systems with Long-Range Coupling

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    We investigate the spread of correlations carried by an excitation in a 1-dimensional lattice system with high on-site energy disorder and long-range couplings with a power-law dependence on the distance (rμ\propto r^{-\mu}). The increase in correlation between the initially quenched node and a given node exhibits three phases: quadratic in time, linear in time, and saturation. No further evolution is observed in the long time regime. We find an approximate solution of the model valid in the limit of strong disorder and reproduce the results of numerical simulations with analytical formulas. We also find the time needed to reach a given correlation value as a measure of the propagation speed. Because of the triple phase evolution of the correlation function the propagation changes its time dependence. In the particular case of μ=1\mu=1, the propagation starts as a ballistic motion, then, at a certain crossover time, turns into standard diffusion

    Modular endolysin of Burkholderia AP3 phage has the largest lysozyme-like catalytic subunit discovered to date and no catalytic aspartate residue

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    Endolysins are peptidoglycan-degrading enzymes utilized by bacteriophages to release the progeny from bacterial cells. The lytic properties of phage endolysins make them potential antibacterial agents for medical and industrial applications. Here, we present a comprehensive characterization of phage AP3 modular endolysin (AP3gp15) containing cell wall binding domain and an enzymatic domain (DUF3380 by BLASTP), both widespread and conservative. Our structural analysis demonstrates the low similarity of an enzymatic domain to known lysozymes and an unusual catalytic centre characterized by only a single glutamic acid residue and no aspartic acid. Thus, our findings suggest distinguishing a novel class of muralytic enzymes having the activity and catalytic centre organization of DUF3380. The lack of amino acid sequence homology between AP3gp15 and other known muralytic enzymes may reflect the evolutionary convergence of analogous glycosidases. Moreover, the broad antibacterial spectrum, lack of cytotoxic effect on human cells and the stability characteristics of AP3 endolysin advocate for its future application development

    The Antibacterial Effect of PEGylated Carbosilane Dendrimers on P. aeruginosa Alone and in Combination with Phage-Derived Endolysin

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    The search for new microbicide compounds is of an urgent need, especially against difficult-to-eradicate biofilm-forming bacteria. One attractive option is the application of cationic multivalent dendrimers as antibacterials and also as carriers of active molecules. These compounds require an adequate hydrophilic/hydrophobic structural balance to maximize the effect. Herein, we evaluated the antimicrobial activity of cationic carbosilane (CBS) dendrimers unmodified or modified with polyethylene glycol (PEG) units, against planktonic and biofilm-forming P. aeruginosa culture. Our study revealed that the presence of PEG destabilized the hydrophilic/hydrophobic balance but reduced the antibacterial activity measured by microbiological cultivation methods, laser interferometry and fluorescence microscopy. On the other hand, the activity can be improved by the combination of the CBS dendrimers with endolysin, a bacteriophage-encoded peptidoglycan hydrolase. This enzyme applied in the absence of the cationic CBS dendrimers is ineffective against Gram-negative bacteria because of the protective outer membrane shield. However, the endolysin—CBS dendrimer mixture enables the penetration through the membrane and then deterioration of the peptidoglycan layer, providing a synergic antimicrobial effect
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