Screening and evaluating honokiol from Magnolia officinalis against Nocardia seriolae infection in largemouth bass (Micropterus Salmoides).

Nocardiosis caused by Nocardia seriolae is a major threat to the aquaculture industry. Given that prolonged therapy administration can lead to a growth of antibiotic resistant strains, new antibacterial agents and alternative strategies are urgently needed. In this study, 80 medicinal plants were selected for antibacterial screening to obtain potent bioactive compounds against N. seriolae infection. The methanolic extracts of Magnolia officinalis exhibited the strongest antibacterial activity against N. seriolae with the minimal inhibitory concentration (MIC) of 12.5 µg/ml. Honokiol and magnolol as the main bioactive components of M. officinalis showed higher activity with the MIC value of 3.12 and 6.25 µg/ml, respectively. Sequentially, the evaluation of antibacterial activity of honokiol in vivo showed that honokiol had good biosafety, and could significantly reduce the bacterial load of nocardia-infected largemouth bass (p < .001). Furthermore, the survival rate of nocardia-infected fish fed with 100 mg/kg honokiol was obviously improved (p < .05). Collectively, these results suggest that medicinal plants represent a promising reservoir for discovering active components against Nocardia, and honokiol has great potential to be developed as therapeutic agents to control nocardiosis in aquaculture.

Detection of wavelength in the range from ultraviolet to near infrared light using two parallel PtSe2/thin Si Schottky junctions.

A wavelength sensor as a representative optoelectronic device plays an important role in many fields including visible light communication, medical diagnosis, and image recognition. In this study, a wavelength-sensitive detector with a new operation mechanism was reported. The as-proposed wavelength sensor which is composed of two parallel PtSe2/thin Si Schottky junction photodetectors is capable of distinguishing wavelength in the range from ultraviolet to near infrared (UV-NIR) light (265 to 1050 nm), in that the relationship between the photocurrent ratio of both photodetectors and incident wavelength can be numerically described by a monotonic function. The unique operation mechanism of the thin Si based wavelength sensor was unveiled by theoretical simulation based on Synopsys Sentaurus Technology Computer Aided Design (TCAD). Remarkably, the wavelength sensor has an average absolute error of ±4.05 nm and an average relative error less than ±0.56%, which are much better than previously reported devices. What is more, extensive analysis was performed to reveal how and to what extent the working temperature and incident light intensity, and the thickness of the PtSe2 layer will influence the performance of the wavelength sensor.

Hierarchical CuInS2-based heterostructure: Application for photocathodic bioanalysis of sarcosine.

In this study, on the basis of hierarchical CuInS2-based heterostructure, a novel cathodic photoelectrochemical (PEC) enzymatic bioanalysis of the sarcosine detection was reported. Specifically, heterostructured CuInS2/NiO/ITO photocathode was prepared and sarcosine oxidases (SOx) were integrated for the construction of the enzymatic biosensor. In the bioanalysis, the O2-dependent suppression of the cathodic photocurrent can be observed due to the competition between the as-fabricated O2-sensitive photocathode and the SOx-catalytic event toward O2 reduction. Based on the sarcosine-controlled O2 concentration, a novel photocathodic enzymatic biosensor could be realized for the sensitive and specific sarcosine detection. This work manifested the great potential of CuInS2-based heterostructure as a novel platform for future PEC bioanalytical development and also a PEC method for sarcosine detection, which could be easily extended to numerous other enzymatic systems and to our knowledge has not been reported. This work is expected to stimulate more interest in the design and implementation of numerous CuInS2-based heterostructured photocathodic enzymatic sensing.

Cu Nanoclusters-Encapsulated Liposomes: Toward Sensitive Liposomal Photoelectrochemical Immunoassay.

Herein we report the strategy of liposome-mediated Cu2+-induced exciton trapping upon CdS quantum dots (QDs) for amplified photoelectrochemical (PEC) bioanalysis application. Specifically, the Cu nanoclusters (NCs)-encapsulated liposomes were first fabricated and then processed with antibodies bound to their external surfaces. After the sandwich immunocomplexing, the confined liposomal labels were subjected to sequential lysis treatments for the release of Cu NCs and numerous Cu2+ ions, which were then directed to interact with the CdS QDs electrode. The interaction of Cu2+ ions with CdS QDs could generate CuxS and form the trapping sites to block the photocurrent generation. Since the photocurrent inhibition is closely related with the Cu NCs-loaded liposomal labels, a novel and general "signal-off" PEC immunoassay could thus be tailored with high sensitivity. Meanwhile, a complementary "signal-on" fluorescent detection could be accomplished by measuring the fluorescence intensity originated from the Cu NCs. This work features the first use of Cu NCs in PEC bioanalysis and also the first NCs-loaded liposomal PEC bioanalysis. More importantly, by using other specific ions/reagents-semiconductors interactions, this protocol could serve as a common basis for the general development of a new class of liposome-mediated PEC bioanalysis.