Phenotyping of Methicillin-Resistant Staphylococcus aureus Using a Ratiometric Sensor Array.

Chemical tools capable of classifying multidrug-resistant bacteria (superbugs) can facilitate early-stage disease diagnosis and help guide precision therapy. Here, we report a sensor array that permits the facile phenotyping of methicillin-resistant Staphylococcus aureus (MRSA), a clinically common superbug. The array consists of a panel of eight separate ratiometric fluorescent probes that provide characteristic vibration-induced emission (VIE) profiles. These probes bear a pair of quaternary ammonium salts in different substitution positions around a known VIEgen core. The differences in the substituents result in varying interactions with the negatively charged cell walls of bacteria. This, in turn, dictates the molecular conformation of the probes and affects their blue-to-red fluorescence intensity ratios (ratiometric changes). Within the sensor array, the differences in the ratiometric changes for the probes result in "fingerprints" for MRSA of different genotypes. This allows them to be identified using principal component analysis (PCA) without the need for cell lysis and nucleic acid isolation. The results obtained with the present sensor array agree well with those obtained using polymerase chain reaction (PCR) analysis.

[Studies on hyperspectral characteristics of Microcystis aeruginosa under the cultivation conditions with different phosphorus concentrations].

Microcystis aeruginosa is one of the most common species in the algae-bloom events of domestic lakes. Illumination incubator was used to cultivate M. aeruginosa under conditions of different phosphorus concentrations in the laboratory. Spectroscopic data of culture solutions were collected by GER1500 spectrometer under the sunlight. The study focused on the growth rhythm of M. aeruginosa and the characteristics of spectral variation in the culture solutions. The results showed that low phosphorus concentration (< or =10 microg x L(-1)) is a restricting factor for the growth and reproduction of M. aeruginosa. Moreover, the reflections of spectrum from culture solutions of M. aeruginosa showed significant changes along with cultivation period, such as at the wavelengths of 550, 610, 660, 700-710 and 760 nm.

Self-assembled sialyllactosyl probes with aggregation-enhanced properties for ratiometric detection and blocking of influenza viruses.

Infection and dissemination of influenza viruses (IVs) causes serious health concerns worldwide. However, effective tools for the accurate detection and blocking of IVs remain elusive. Here, we develop a new sialyllactosyl probe with self-assembled core-shell structure for the ratiometric detection and blocking of IVs. N,N'-diaryl-dihydrodibenzo[a,c]phenazines were used to form the core structure by hydrophobic assembly in an aqueous solution with an aggregation-enhanced blue fluorescence mission. Subsequently, dicyanomethylene-4H-pyran-based sialyllactosides were used for self-assembly with the core structure, producing the sialyllactosyl probe that emits a red fluorescence due to Förster resonance energy transfer. The probe developed has been proven to be available for (1) the fluorescence ratiometric detection of IVs through selective interaction with the sialyllactosyl-binding proteins on the virus surface, and (2) effectively blocking the invasion of human-infecting IVs towards host cells as accentuated by the sialyllactosides on the surface of the probes.