In a polymicrobial community, while some bacteria are communicating with neighboring cells (quorum sensing), others are interrupting the communication (quorum quenching), thus creating a constant arms race between intercellular communication. In the past decade, numerous quorum quenching enzymes have been found and initially thought to inactivate the signalling molecules. Though this is widely ...

The effect of ionic activity on the quenching of the quinine dication fluorescence by chloride and bromide ions is examined in solutions of sufficiently low ionic strength to enable ionic activities to be taken into account by means of the Debye-Hückel equation. An equation for the dependence of the Stern-Volmer constant on the ionic strength is derived in a novel way and an iterative, linear l...

Induction of zeaxanthin formation and the associated nonphotochemical quenching in iodoacetamide-treated, non-CO(2)-fixing intact chloroplasts of Lactuca sativa L. cv Romaine is reported. The electron transport needed to generate the required DeltapH for zeaxanthin formation and nonphotochemical quenching are ascribed to the Mehler-ascorbate peroxidase reaction. KCN, an inhibitor of ascorbate p...

The wavelength dependent fluorescence decay properties of bovine prothrombin fragment 1 have been investigated employing a picosecond time-correlated single photon counting technique. All observations are discussed with using the crystal structure (Soriano-Garcia et al., Biochemistry 31:2554-2566, 1992). Fluorescence lifetimes distribution and conventional multiexponential analysis, as well as ...

Nonradiative relaxation and photoluminescence quenching in nanocrystalline powders doped with rare-earth elements are of interest in optical bistability, random laser, and other optoelectronic applications. Here, the luminescence quenching of a one-dimensional random medium made of multilayer nanoparticles sY2O3d doped with rare-earth elements sYb3+d is analyzed by considering the transport, tr...

Quorum quenching (QQ) enzymes, which disrupt the quorum sensing signaling process, have attracted considerable attention as new antimicrobial agents. However, their low catalytic efficiency for quorum sensing molecules remains a challenge. Herein, we present an antisense RNA-based high-throughput screen system for directed evolution of a quorum quenching enzyme. The screening system was constru...

Herein we report a novel fluoranthene-based fluorescent fluorophore 7,10-bis(4-bromophenyl)-8,9-bis[4-(hexyloxy)phenyl]fluoranthene (S(3)) and its remarkable properties in applications of explosive detection. The sensitivity towards the detection of nitroaromatics (NACs) was evaluated through fluorescence quenching in solution, vapor, and contact mode approaches. The contact mode approach using...

Experimental rate coefficients for the removal of NH(a (1)Delta) and ND(a (1)Delta) in collisions with H and D atoms are presented; all four isotope combinations are considered: NH+H, NH+D, ND+H, and ND+D. The experiments were performed in a quasistatic laser-flash photolysis/laser-induced fluorescence system at low pressures. NH(a (1)Delta) and ND(a (1)Delta) were generated by photolysis of HN...

Experimental rate coefficients for the removal of NH a 1 and ND a 1 in collisions with H and D atoms are presented; all four isotope combinations are considered: NH+H, NH+D, ND+H, and ND+D. The experiments were performed in a quasistatic laser-flash photolysis/laser-induced fluorescence system at low pressures. NH a 1 and ND a 1 were generated by photolysis of HN3 and DN3, respectively. The tot...

In this paper, the interaction of lomefloxacin (LMF) and/or cefazolin (CFZ) with bovine serum albumin (BSA) was studied by fluorescence quenching in combination with UV-vis spectroscopic method under simulative physiological conditions. The fluorescence quenching constants, binding distance, and binding constants for BSA–LMX and/or CFZ systems were determined. The fluorescence quenching of BSA ...