AIE -active TPA modified Schiff base for successive sensing of Cu2+ and His via an on-off-on method and its application in bioimaging.

In this article, a novel triphenylamine-modified salicylaldehyde Schiff base 2-(((4-(diphenylamino)phenyl)imino)methyl)-4-(pyridine-4-yl)phenol (HL) was synthesized and structurally characterized. HL possessed D-π-A structure and exhibited typical AIE property in THF/H2O. It was applied to selectively recognize Cu2+ through an on-off mode in THF/H2O (1/9, v/v), and the fluorescence attenuation was attributed to a paramagnetic quenching effect of Cu2+ together with the abatement of HL aggregates. Hence, the detection limit achieved was as low as 1.32 × 10-7 M. The spectroscopic and ESI-HRMS results revealed a 1 : 2 complexation ratio of Cu2+ with HL. The mechanism for sensing Cu2+ was further confirmed by performing DFT calculations. Owing to the large affinity between Cu2+ and His, the resultant CuL2 system was further used to detect His via the off-on method based on the displacement of ligands. The detection limit for His reached 5.14 × 10-8 M. Furthermore, HL was available to prepare handy indicator papers for the on-site recognition of Cu2+ and His. Confocal fluorescent imaging demonstrated that HL could sequentially respond to intracellular Cu2+ and His.

[Stem characteristics of different wheat varieties and its relationship with lodging-resistance.] / ä¸åŒå°éº¦å“ç§èŒŽç§†ç‰¹æ€§åŠå ¶ä¸ŽæŠ—å€’æ€§çš„å ³ç³».

Taking four outstanding varieties Aikang 58, Zhoumai 18, Yumai 49 and Bainong 418 from Huanghuai wheat area as test objects, the lodging-resistance traits of different varieties at different growth stages were investigated by combining field and laboratory methods. The results showed that stem mechanical strength was at a high level between flowering and 20 days after flowering, declined significantly in 30 days after flowering. The lodging index was minimal in flowering period, maximal in 30 days after flowering, and was at an intermediate level in the other two periods. Correlation analysis showed that culm mechanical strength was significantly negatively correlated with the height of gravity, and significantly positively correlated with cellulose and lignin contents at the flowering, lodging index was significantly positively correlated with the internode length, plant height and height of gravity, but significantly negatively correlated with cellulose and lignin contents. Ten days and 20 days after flowering, the culm mechanical strength was negatively correlated with the internode length, plant height and height of gravity, and significantly positively correlated with stem diameter, cellulose content, hemicelluloses content and lignin content, while the lodging index was just the opposite. Thus, making lodging-resistance related stem characteristics at each stage clear, could provide a basis for breeding lodging-resistance and high yield varieties in Huanghuai wheat area.

A tetrazole-based fluorescence "turn-on" sensor for Al(III) and Zn(II) ions and its application in bioimaging.

A tetrazole derivative 1-[(1H-tetrazol-5-ylimino)methyl]naphthalen-2-ol (H2L) as a fluorescent chemosensor for Al(3+) in DMSO and Zn(2+) in DMF was designed and synthesized. From (1)H NMR data, the Job plot and the ESI-MS spectrum, 1 : 1 stoichiometric complexation between H2L and Al(3+)/Zn(2+) was found in DMSO and DMF, respectively. The theoretical calculations at the level of B3LYP/6-311G** for the ground state and TD-B3LYP/6-311G** for the excited state revealed the sensing mechanism is the inhibition of excited state intramolecular proton transfer (ESIPT). And the possible fluorescent species formed in the DMSO and DMF solutions were deduced to be [Al(HL)(OH)(NO3)(H2O)(DMSO)] and [Zn(HL)(OH)(H2O)(DMF)]. What's more, it is confirmed that H2L could be used to detect Al(3+) and Zn(2+) in cells by bioimaging.

A highly selective fluorescent chemosensor for Al(III) ion and fluorescent species formed in the solution.

A chemosensor for the Al(3+) ion, 1-[(3-hydroxypyridin-2-ylamino)methylene]naphthalen-2(1H)-one (H2L), based on inhibited excited-state intramolecular proton transfer was synthesized. The experimental and theoretical calculations at B3LYP+PCM/6-31G(d) revealed that Al(3+) and H2L form a 1:1 complex, [AlL(OH)(H2O)]2, in dimethyl sulfoxide that exhibits two remarkably enhanced fluorescent emissions at 523 and 553 nm. It is confirmed that H2L could be used to detect Al(3+) ions in cells by bioimaging.

Identification of an important site for function of the type 2C protein phosphatase ABI2 in abscisic acid signalling in Arabidopsis.

It is known that the clade A protein phosphatase 2Cs (PP2Cs), including ABI1 and ABI2 and other PP2C members, are key players that function directly downstream of the PYR/PYL/RCAR abscisic acid (ABA) receptors. Here, identification of a crucial site for function of ABI2 protein phosphatase in ABA signalling is reported. It was observed that a calcium-dependent protein kinase (CDPK) phosphorylation site-like motif (CPL) in the ABI2 molecule is required for the interactions of ABI2 with the two members of the ABA receptors PYL5 and PYL9 and with a downstream protein kinase SnRK2.6, and for the catalytic activity of ABI2 in vitro, as well as for the response of ABI2 to the ABA receptors PYL5/PYL9 in relation to the ABA receptor-induced inhibition of the ABI2 phosphatase activity. Further, genetic evidence was provided to demonstrate that this CPL is required for the function of ABI2 to mediate ABA signalling. These data reveal that this CPL is an important site necessary for both the phosphatase activity of ABI2 and the functional interaction between ABI2 and PYL5/9 ABA receptors, providing new information to understand primary events of ABA signal transduction.