ABSTRACT
The study of effects of Ca2+ and Mg2+ on antifungal activity of lactic acid bacteria (LAB) isolates and their associations revealed inducing and inhibiting effects on antifungal activity. The addition of Ca2+ essentially inhibited the antifungal effect of L. rhamnosus MDC9661 but stimulated the activity of RIN-2003-Ls, MDC9632 and MDC9633 strains, as well as their associations. Mg2+ partly increased the inhibitory activity of LAB isolates, while the addition of ions combination did not cause changes of their antifungal activity. The supplementation of Ca2+ stimulated the antifungal effect of most associations against Penicillium sp., Trichoderma viride, Geotrichum candidum, and Aspergillus flavus compared with the native conditions. The addition of Mg2+ induced the antifungal activity of RIN-2003-Ls, MDC9632, MDC9633, and INR-2010-Tsov-G-St combinations. The antifungal effects of most associations were increased in the presence of ions mixture. The natural LAB associations including VKPM B-3386, MDC9632, and MDC9633 could not suppress the growth of any tested mold; however, the supplementation of ions combination revealed their antifungal effect against all kinds of molds. The finding of substantial stimulation of the most LAB associations antifungal effect by metal ions can be basis for creation of new effective antifungal preparations by the supplementation of ions combined mixture.
Subject(s)
Antifungal Agents/pharmacology , Cations, Divalent/pharmacology , Lactobacillales/physiology , Antibiosis , Calcium Chloride/pharmacology , Fungi/drug effects , Magnesium Chloride/pharmacology , Microbial Sensitivity TestsABSTRACT
C-type lectin from hen egg shell as a recognition ligand for detection of St. aureus was applied. Three approaches for detection of bacteria were used and the sensitivities of the assays were compared. Two of them included spherical and anisotropic silver nanoparticles sensitized by lectin. In these cases the optical changes as a result of interaction of sensitized nanoparticles with bacteria were measured. In the third approach hybrid system of CdSe quantum dots-anisotropic silver nanoparticles sensitized by lectin was applied. Here fluorescent changes as a result of resonance energy transfer between nanoparticles as consequence of their interaction with bacteria were measured. The data demonstrate that assays with spherical silver nanoparticles permit to detect St. aureus in the range of 6 × 104/mL-2 × 107/mL, anisotropic silver nanoparticles in the range of 2 × 105/mL-1 × 108/mL, CdSe-Ag hybrid system in the range of 6 × 103/mL-2 × 107/mL. The data demonstrate that hybrid system CdSe-Ag with resonance energy transfer provides the best sensitivity.
Subject(s)
Cadmium Compounds/chemistry , Lectins, C-Type/chemistry , Metal Nanoparticles/chemistry , Quantum Dots/chemistry , Selenium Compounds/chemistry , Silver/chemistry , Staphylococcus aureus/isolation & purification , Animals , Chickens , Fluorescence Resonance Energy Transfer/methods , Humans , Staphylococcal Infections/microbiologyABSTRACT
A method of bacteria detection by sensitized anisotropic silver nanoparticles is presented. Anisotropic silver nanoparticles with two bands of surface plasmon resonance (SPR) are prepared and sensitized with potato lectin. These nanoparticles are able to detect three bacterial species: Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The interaction of these bacteria with such nanoparticles induces drastic changes in optical spectra of nanoparticles that are correlated with bacteria titer. The maximal sensitivity is observed for S. aureus (up to 1.5×10(4) mL(-1)).
