Design Mechanism and Property of the Novel Fluorescent Probes for the Identification of Microthrix Parvicella In Situ

Abstract

In this study, two novel fluorescent probes, probe A and probe B were designed, synthesized and characterized, based on Microthrix parvicella (M. parvicella) preferring to utilize long-chain fatty acid (LCFA), for the labeling of M. parvicella in activated sludge. The molecular structure of probe A and probe B include long-chain alkane and LCFA, respectively. The results indicated that probe A and probe B had a large stokes shift of 118 nm and 120 nm and high quantum yield of 0.1043 and 0.1058, respectively, which were significantly helpful for the fluorescent labeling. As probe A was more stable than probe B in activated sludge, and the fluorescence intensity keep stable during 24 h, probe A was more suitable for labeling M. parvicella in situ. In addition, through the Image Pro Plus 6 (IPP 6) analysis, a quantitative relationship was established between sludge volume index (SVI) and integral optical density (IOD) of the labeled M. parvicella in activated sludge samples. The relationship between IOD and SVI conforms to Logistic curve (R2 = 0.94).

Designing of New Optical Immunosensors Based on 2-Amino-4-(anthracen-9-yl)-7-hydroxy-4H-chromene-3-carbonitrile for the Detection of Aeromonas hydrophila in the Organs of Oreochromis mossambicus Fingerlings

“…Generally, proteins, bacterial-based tagging, will give a large Stoke’s shift greater than 200 nm-based. 45−47 Likewise, our anti-AH tagged with AHC has shown excellent Stoke’s shift, and the respective emission spectra are shown in Figure 2.…”

“…Interaction of all of these pathogens slightly quenches the initial fluorescent intensity of anti-AH–AHC which may be because of nonfluorescent complex formation via FRET quenching. 45 The competitive test was performed by incubating 1 equiv of 2 mL of anti-AH–AHC with 1 equiv (10 μL, 10 –1 CFU/g) of AH and 1 equiv (10 μL, 10 –1 CFU/g) of all interfering pathogens, and the corresponding fluorescent intensity changes were recorded. Remarkably, there was no quenching in the fluorescent intensity for anti-AH–AHC.…”

An Optical Biosensing Strategy Based on Selective Light Absorption and Wavelength Filtering from Chromogenic Reaction

“…Therefore, the achievement of high portability, cost-effectiveness, and user-friendliness are considered major aims for robust analytical performance in biosensor technology research. Currently, due to good analytical performance including high accuracy and signal-to-noise ratio, optical biosensing technologies such as fluorescence analysis [ 1 , 2 , 3 ], surface plasmon resonance–based affinity biosensing [ 4 , 5 , 6 ], and ultraviolet/visible (UV/Vis) spectrophotometric biosensing are extensively investigated as promising approaches to the realization of point-of-care (POC) diagnostics. Because the robust analytical performance of these optical biosensing technologies can be attained only by means of a specific optical-signal-transducing technology (which has several drawbacks including low cost-effectiveness, high complexity, high power consumption, low portability, and poor user-friendliness), the applications of these conventional optical biosensing technologies to POC diagnostics are limited [ 7 , 8 , 9 , 10 ].…”

A novel fluorescent long-chain fatty acid-substituted dye: labeling and biodegrading ofMicrothrix parvicella

“…We recently reported some uorescent probes with long-chain alkanes for labeling M. parvicella in sludge samples. [11][12][13] Nielsen 14 reported that the lipases on M. parvicella can catalyze the hydrolyzation of oils and lipid compounds into long-chain fatty acids (LCFAs) and transport them into cells as normal lipids. That is, M. parvicella has affinity for LCFAs via lipases.…”

“…Two other probes FP2 (ref. 13) and FP3 (ref. 19) were also used to study the impact of side-chain length on the labeling efficiency, identication, and metabolism of M. parvicella (Fig.…”