High-performance photoelectrochemical immunosensor based on featured photocathode-photoanode operating system.

Photocathodic immunosensors generally exhibit fortified anti-interference abilities than photoanodic ones against the detection in biological specimens. Yet, the weak photocurrent signals of the photocathodes have limited evidently the detection performance. Herein, an efficient and feasible photoelectrochemical (PEC) immunosensor was developed on the basis of the featured photocathode-photoanode operating system. In the proposal, the elaborated PEC immunosensor integrated photocathode with photoanode, and the immune recognition occurred just on the photocathode. To illustrate the performance, α-fetoprotein (AFP) was selected as a target antigen (Ag) for detection. TiO2 nanoparticles were decorated with AgInS2 quantum dots (AIS QDs) to fabricate the TiO2/AIS photoanode, and the carbon nanotubes (CNTs) were modified with CuInS2 nanoflowers (CIS NFs) to prepare the CNT/CIS photocathode for the capture AFP antibody (Ab) anchoring. Target Ag detection depended on significant decrease of the photocurrent signal produced by large steric hindrance of the captured AFP molecules. Coupling excellent photoelectric property with anti-interference ability in this elegant PEC immunosensor, sensitive and specific probing of target Ag was realized. The proposed photocathode-photoanode integrating strategy provides a promising way to explore other high-performance PEC immunosensors against the detection in biological matrixes.

Bottom-up redistribution of biomass optimizes energy allocation, water use and yield formation in dryland wheat improvement.

BACKGROUND: Modern wheat cultivars have been developed having distinct advantages in many aspects under drought stress, such as plasticity in biomass allocation and root system architecture. A better understanding of the biomass allocation mechanisms that enable modern wheat to achieve higher yields and yield-based water use efficiency (WUEg ) is essential for implementing best management strategies and identifying phenotypic traits for cultivar improvement. We systematically investigated the biomass allocation, morphological and physiological characteristics of three ploidy wheat genotypes under 80% and 50% field water-holding capacity (FC) conditions. Some crucial traits were also assessed in a complementary field experiment. RESULTS: The diploid and tetraploid genotypes were found to allocate more biomass to the root system, especially roots in the topsoil under drought stress. Our data illustrated that lower WUEg and yield of these old genotypes were due to excessive investment in the root system, which was associated with severely restricted canopy development. Modern hexaploid genotypes were found to allocate smaller biomass to roots and larger biomass to shoots. This not only ensured the necessary water uptake, but also allowed the plant to distribute more assimilates and limited water to the shoots. Therefore, the hexaploid genotypes have evolved a stable plant canopy structure to optimize WUEg and grain yield. CONCLUSION: This study demonstrated that the biomass shift from below ground to above ground or a more balanced root:shoot ratio tended to optimize water use and yield of the modern cultivars. This discovery provides potential guidance for future dryland wheat breeding and sustainable management strategies. © 2021 Her Majesty the Queen in Right of Canada Journal of The Science of Food and Agriculture © 2021 Society of Chemical Industry. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.

Active constituents of Zanthoxylum nitidium from Yunnan Province against leukaemia cells in vitro.

Zanthoxylum nitidium (Roxb.) DC (Rutaceae) is well known for inhibiting the proliferation of human gastric, liver, kidney and lung cancer cells, though research on its potential use in treating leukaemia is relatively rare. Twenty-six compounds were isolated from the chloroform and petroleum ether extracts of the roots and leaves of Z. nitidium (Zanthoxylum nitidium). They were ( +)-9'-O-transferuloyl-5, 5'-dimethoxylaricriresinol (1), 8-(3'-oxobut-1'-en-1'-yl)-5, 7-dimethoxy-coumarin (2), 5, 7, 8-trimethoxy-coumarin (3), 5-(3', 3'-dimethyl-2'-butenyloxy)-7, 8-dimethoxy-coumarin (4), 2-(5-methoxy-2-methyl-1H-indol-3-yl) methyl acetate (5), 2'-(5, 6-dihydrochleletrythrine-6-yl) ethyl acetate (6), 6-acetonyldi-hydrochelerythrine (7), 6ß-hydroxymethyldihydronitidine (8), bocconoline (9), zanthoxyline (10), O-methylzanthoxyline (11), rhoifoline B (12), N-nornitidine (13), nitidine (14), chelerythrine (15), 4-hydroxyl-7,8-dimethoxy-furoquinoline (16), dictamnine (17), γ-fagarine (18), skimmianine (19), robustine (20), R-( +)-platydesmine (21), 4-methoxyl-1-methyl-2-quinoline (22), 4-methoxy-2-quinolone (23), liriodenine (24), aurantiamide acetate (25), 10-O-demethyl-12-O-methylarnottianamide (26). Four among them, compounds 4 - 6 and 16, were first confirmed in this study by UV, IR, 1D, 2D NMR and HR-ESI-MS spectra. Compounds 1 - 2 and 11 were isolated from Z. nitidium for the first time. Of the assayed compounds, 1, 2, 9, 10, 14, 15 and 24, exhibited good inhibitory activities in the leukaemia cell line HEL, whereas compound 14 (IC50: 3.59 µM) and compound 24 (IC50: 15.95 µM) exhibited potent inhibitory activities. So, to further investigate the possible mechanisms, cell cycle and apoptosis assays were performed, which indicated that compound 14 causes obvious S-phase arrest in HEL cells and induced apoptosis, whereas compound 24 only induced apoptosis. The present results suggested both compounds 14 and 24 are promising potential anti-leukaemia drug candidates.