[Genome-wide identification and effect of MdPEPC family genes during axillary bud outgrowth in apple (Malus domestica Borkh.)].

The PEPC family proteins are ubiquitous in various plants and play an important role in the process of photosynthetic carbon assimilation and have many non-photosynthetic biological functions. However, PEPC genes have not been reported in apple. In this study, the members of apple MdPEPC family were identified based on the new apple genome data by bioinformatics analysis, and their expression patterns in different tissues and the apple axillary bud transcriptome treated by decapitation and TDZ (cytokinin) were analyzed in order to explore the role of MdPEPC genes in apple axillary bud outgrowth. The results showed that 6 MdPEPC family members were identified in apple, which distributed on 6 different chromosomes, and had similar physicochemical characteristics. Phylogenetic tree and sequence alignment analysis showed that the MdPEPC could be divided into two subgroups (Group Ⅰ and Group Ⅱ), in which four members in MdPEPC family were clustered into Group Ⅰ, belonging to plant-type PEPCs. However, MdPEPC4 and MdPEPC5 were clustered into Group Ⅱ with AtPPC4, belonging to bacterial-type PEPCs. There were 7 pairs of fragments repeats among MdPEPC members, but no tandem repeats existed. The promoter cis-acting element analysis showed that MdPEPC genes were not only affected by light and stress, but also regulated by multiple hormones. The expression profiles showed that all MdPEPCs except MdPEPC4 and MdPEPC5 were expressed in different apple tissues. Transcriptome data analysis showed that the expression levels of MdPEPC1 and MdPEPC3 were up-regulated after decapitation and TDZ treatment, whereas MdPEPC2 was significantly down-regulated at 48 h after treatments. In conclusion, MdPEPC1, MdPEPC2 and MdPEPC3 were selected as the candidate genes involved in axillary bud outgrowth regulation for further study.

Piezotronic-effect enhanced drug metabolism and sensing on a single ZnO nanowire surface with the presence of human cytochrome P450.

Cytochromes P450 (CYPs) enzymes are involved in catalyzing the metabolism of various endogenous and exogenous compounds. A rapid analysis of drug metabolism reactions by CYPs is required because they can metabolize 95% of current drugs in drug development and effective therapies. Here, we describe a study of piezotronic-effect enhanced drug metabolism and sensing by utilizing a single ZnO nanowire (ZnO NW) device. Owing to the unique hydrophobic feature of a ZnO NW that provides a desirable "microenvironment" for the immobilization of biomolecules, our device can effectively stimulate the tolbutamide metabolism by decorating a ZnO NW with cytochrome P4502C9/CYPs reductase (CYP2C9/CPR) microsomes. By applying an external compressive strain to the ZnO nanowire, the piezotronic effect, which plays a primary role in tuning the transport behavior of a ZnO NW utilizing the created piezoelectric polarization charges at the local interface, can effectively enhance the performance of the device. A theoretical model is proposed using an energy band diagram to explain the experimental data. This study provides a potential approach to study drug metabolism and trace drug detection based on the piezotronic effect.

Detection of human immunoglobulin G by label-free electrochemical immunoassay modified with ultralong CuS nanowires.

Ultralong copper sulfide nanowires (CuSNWs) were synthesized via a simple wet chemical route. Due to the desired surface charge characteristics and attractive electrocatalytic activity toward the oxidation of ascorbic acid, such ultralong one-dimensional nanomaterials provided an interesting platform for electrochemical signal amplification. By immobilizing an anti-IgG antibody on the chitosan (CS)-CuSNWs film, a novel label-free electrochemical immunosensor was thus developed for detection of human immunoglobulin G (IgG). Various experimental parameters were studied, and the interference effects from other proteins were checked. Under the optimum conditions, the decrease of the amperometric signal presented a linear relationship in the IgG concentration range of 0.001-320 ng mL-1 with a detection limit of 0.1 pg mL-1 (S/N = 3). The practical application of the fabricated immunosensor has also been demonstrated by detecting IgG in real human serum samples. The satisfactory results hint the significant potential in clinical analysis.

Detection of H2O2 at the nanomolar level by electrode modified with ultrathin AuCu nanowires.

Bimetallic AuCu nanowires (AuCuNWs) are synthesized via a facile water solution method at room temperature. Enhanced electrocatalytic activity is observed toward the oxidation of H2O2, which makes the AuCu nanowire, along with its unique catalytic properties, intriguing bifunctional mechanism, and surface atomic construction, a promising platform for the amplification of interfacing signal. A highly sensitive H2O2 biosensor is thus developed on the base of the as-prepared AuCuNW catalyst. A very low real determination limit (2.0 nM) was reached, and a linear range as wide as 5 orders of magnitude was demonstrated. In addition, a trace amount of H2O2, which was released from Raw 264.7 cells, was selectively detected, hinting at the possible applications for real-time quantitative detection of H2O2 in a biological environment.

A porous PdO microrod-based electrochemical sensor for nanomolar-level Cu2+ released from cells.

Highly porous PdO microrods (PoPdOMRs) with a well-defined morphology, large surface area and active sites were synthesized via a facile wet chemical method for the first time. A sensitive and selective electrochemical sensor was thus developed by using the PoPdOMRs as a sensing platform. The PoPdOMR modified sensor exhibited a response time of less than 8 s, a linear range between 1.0 × 10-9 and 8.0 × 10-5 mM, and a sensitivity up to 112 µA µM-1 cm-2 for the determination of Cu2+. A sound sensing selectivity towards Cu2+ in the presence of interfering ions was also observed. On the basis of this sensor, the trace amount of Cu2+ released from Raw 264.7 cells was successfully recorded, which makes the PoPdOMR electrocatalyst promising for the development of effective electrochemical sensors for a wide range of potential applications in bioanalysis and environmental chemistry.