Multi-stimuli-responsive programmable biomimetic actuator.

Untethered small actuators have various applications in multiple fields. However, existing small-scale actuators are very limited in their intractability with their surroundings, respond to only a single type of stimulus and are unable to achieve programmable structural changes under different stimuli. Here, we present a multiresponsive patternable actuator that can respond to humidity, temperature and light, via programmable structural changes. This capability is uniquely achieved by a fast and facile method that was used to fabricate a smart actuator with precise patterning on a graphene oxide film by hydrogel microstamping. The programmable actuator can mimic the claw of a hawk to grab a block, crawl like an inchworm, and twine around and grab the rachis of a flower based on their geometry. Similar to the large- and small-scale robots that are used to study locomotion mechanics, these small-scale actuators can be employed to study movement and biological and living organisms.

Barnyard grass stress up regulates the biosynthesis of phenolic compounds in allelopathic rice.

Allelopathic rice cultivar PI312777 (PI) and non-allelopathic rice cultivar Lemont (Le) were mixed with barnyard grass (Echinochloa crus-galli L., BYG) at various ratios (rice:weed ratios of 4:1, 2:1, and 1:1) in hydroponic cultures. The expression of four genes, i.e. phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H), ferulic acid 5-hydroxylase (F5H), and caffeic acid O-methyltransferases (COMT), which are involved in the biosynthesis of the phenolic compounds in rice, were evaluated by a quantitative real-time polymerase chain reaction (qRT-PCR). The contents of phenolic compounds in leaves, roots, and culture solutions of the two rice cultivars were determined using high performance liquid chromatography (HPLC). The results showed that all of the four genes were up-regulated in leaves and roots of the allelopathic rice PI at all rice:weed ratios. However, three of the four genes, C4H, F5H, and COMT, were down-regulated in the leaves and roots of the non-allelopathic rice Le. The degree to which PAL was up-regulated in leaves and roots was much higher in PI than in Le. The contents of phenolic compounds in PI leaves, roots, and culture solutions were higher than that in Le leaves, roots, and culture solutions. The higher expression of the genes involved in the phenylpropanoid metabolism and the higher contents of phenolic compounds in PI are consistent with the higher inhibitory rates of PI on BYG. These results indicate that the PAL gene in PI is more sensitive to BYG stress than in Le, and barnyard grass up regulates the biosynthesis of phenolic compound in allelopathic rice.

Characterization of metaproteomics in crop rhizospheric soil.

Soil rhizospheric metaproteomics is a powerful scientific tool to uncover the interactions between plants and microorganisms in the soil ecosystem. The present study established an extraction method suitable for different soils that could increase the extracted protein content. Close to 1000 separate spots with high reproducibility could be identified in the stained 2-DE gels. Among the spots, 189 spots representing 122 proteins on a 2-DE gel of rice soil samples were successfully identified by MALDI-TOF/TOF-MS. These proteins mainly originated from rice and microorganisms. They were involved in protein, energy, nucleotide, and secondary metabolisms, as well as signal transduction and resistance. Three characteristics of the crop rhizospheric metaproteomics seemed apparent: (1) approximately one-third of the protein spots could not be identified by MALDI-TOF/TOF/MS, (2) the conservative proteins from plants formed a feature distribution of crop rhizospheric metaproteome, and (3) there were very complex interactions between plants and microorganisms existing in a crop rhizospheric soil. Further functional analysis on the identified proteins unveiled various metabolic pathways and signal transductions involved in the soil biotic community. This study provides a paradigm for metaproteomic research on soil biology.