The basic helix-loop-helix (bHLH) proteins, a large transcription factors family, are involved in plant growth and development, and defensive response to various environmental stresses. The ...resurrection plant Myrothamnus flabellifolia is known for its extremely strong drought tolerance, but few bHLHs taking part in abiotic stress response have been unveiled in M. flabellifolia.
In the present research, we cloned and characterized a dehydration-inducible gene, MfbHLH38, from M. flabellifolia. The MfbHLH38 protein is localized in the nucleus, where it may act as a transcription factor. Heterologous expression of MfbHLH38 in Arabidopsis improved the tolerance to drought and salinity stresses, as determined by the studies on physiological indexes, such as contents of chlorophyll, malondialdehyde (MDA), proline (Pro), soluble protein, and soluble sugar, water loss rate of detached leaves, reactive oxygen species (ROS) accumulation, as well as antioxidant enzyme activities. Besides, MfbHLH38 overexpression increased the sensitivity of stomatal closure to mannitol and abscisic acid (ABA), improved ABA level under drought stress, and elevated the expression of genes associated with ABA biosynthesis and ABA responding, sucha as NCED3, P5CS, and RD29A.
Our results presented evidence that MfbHLH38 enhanced tolerance to drought and salinity stresses in Arabidopsis through increasing water retention ability, regulating osmotic balance, decreasing stress-induced oxidation damage, and possibly participated in ABA-dependent stress-responding pathway.
Abstract
In transition metal compounds, due to the interplay of charge, spin, lattice and orbital degrees of freedom, many intertwined orders exist with close energies. One of the commonly observed ...states is the so-called nematic electron state, which breaks the in-plane rotational symmetry. This nematic state appears in cuprates, iron-based superconductor, etc. Nematicity may coexist, affect, cooperate or compete with other orders. Here we show the anisotropic in-plane electronic state and superconductivity in a recently discovered kagome metal CsV
3
Sb
5
by measuring
c
-axis resistivity with the in-plane rotation of magnetic field. We observe a twofold symmetry of superconductivity in the superconducting state and a unique in-plane nematic electronic state in normal state when rotating the in-plane magnetic field. Interestingly these two orders are orthogonal to each other in terms of the field direction of the minimum resistivity. Our results shed new light in understanding non-trivial physical properties of CsV
3
Sb
5
.
Phytochrome-interacting factors (PIFs), a subfamily of basic helix-loop-helix (bHLH) transcription factors (TFs), play critical roles in regulating plant growth and development. The resurrection ...plant
possesses a noteworthy tolerance to desiccation, but no PIFs related to the response to abiotic stress have been functionally studied. In this study, a dehydration-inducible
gene,
, was cloned and characterized. Subcellular localization assay revealed that MfPIF1 is localized predominantly in the nucleus. Overexpression of
in
led to enhanced drought and salinity tolerance, which was attributed to higher contents of chlorophyll, proline (Pro), soluble protein, and soluble sugar, activities of antioxidant enzymes as well as lower water loss rate, malondialdehyde (MDA) content, and reactive oxygen species (ROS) accumulation in transgenic lines compared with control plants. Moreover,
decreased stomatal aperture after drought and abscisic acid (ABA) treatment, and increased expression of both ABA biosynthesis and ABA-responsive genes including
,
, and
. Overall, these results indicated that
may act as a positive regulator to drought and salinity responses, and therefore could be considered as a potential gene for plant genetic improvement of drought and salinity tolerance.
Biomimetic assembly of high-quality nanosheets into nacre-like structures can produce macroscopic films with favorable mechanical and optical performances due to the intrinsic properties and high ...level of ordering of the nanoscale building blocks. Natural ground mica is abundant and exhibits great application potential. However, large size and low aspect ratio greatly limit its biomimetic assembly. Moreover, exfoliation of ground mica into high-quality nanosheets remains a significant challenge. Here, we report that large-scale exfoliation of ground mica into mono- or few-layered mica nanosheets with a production rate of ~1.0 g h
can be successfully achieved. The mica nanosheets are then assembled into strong biomimetic polymeric mica film that inherits the high electric insulation, excellent visible transmittance, and unique ultraviolet-shielding properties of natural mica. Its overall performance is superior to that of natural sheet mica and other biomimetic films, making the polymeric mica film a suitable substrate for flexible and transparent devices.
In photo‐induced olefin synthesis, the photocatalysts with high triplet energy could cause the isomerization of olefins. This study demonstrates a new quinoxalinone photocatalytic system for highly ...stereoselective alkenes preparation from alkenyl sulfones and alkyl boronic acids. Our photocatalyst could not convert the thermodynamically favored E‐olefin to Z‐olefin, guaranteeing the high E‐configuration selectivity of the reaction. There is weak interaction between boronic acids and quinoxalinone according to NMR experiments, probably decreasing the oxidation potential of boronic acids. This system can be further extended to the allyl and alkynyl sulfones to give corresponding alkenes and alkynes.
An efficient method for the synthesis of highly E‐selective olefins directly utilizing alkyl boronic acids as radical precursors was developed, catalysed by novel quinoxalinone‐type catalyst.
Described herein is an effective and green reaction between diketones, amines and bio‐renewable glyoxal, affording a wide range of 2‐pyrrolin‐5‐ones and releasing water as the only byproduct. The ...reaction features step‐economy, high efficiency, mild conditions, broad substrate scope, hazardous waste avoiding and easy scale‐up. The further transformation between the products and aldehydes can be potentially applied for fluorescent dye synthesis.
An efficient and environmentally benign method was developed for the synthesis of 2‐pyrrolin‐5‐ones from dicarbonyl compounds, bio‐renewable glyoxal, and amines. More than 25 new 2‐pyrrolin‐5‐one compounds were synthesized in good to high yields under mild conditions.
A multi‐talented system: An efficient copper‐catalyzed tandem trifluoromethylation/annulation of an electron‐deficient aromatic ring has been developed. This method provides a powerful and ...straightforward way to synthesize trifluoromethylated 1,2‐benzothiazinane dioxides under mild conditions (see scheme). The mechanism was investigated by a series of kinetic experiments and isotopic labeling studies.
Hypoxia is a common feature of solid tumors. It is closely related to tumor progression. Exosomal microRNAs derived from cancers are considered to be mediators between cancer cells and the tumor ...microenvironment. In addition, the number of tumor-associated macrophages (TAMs) in the tumor microenvironment has also been demonstrated to correlate with tumor development. However, the relationship between tumor-secreted exosomes and TAM polarization under hypoxic conditions during tumor progression is not clear. Herein, we demonstrated that hypoxia induces the high expression of microRNA-940 (miR‑940) in exosomes derived from epithelial ovarian cancer (EOC). We also found that miR‑940 is highly expressed in exosomes isolated from ascites of EOC patients. Moreover, the overexpression of miR‑940 in macrophages delivered by exosomes stimulated M2 phenotype polarization, while the M2 subtype macrophages promoted EOC proliferation and migration. These results highlight the function of hypoxia in enhancing the high level of expression of miR‑940 in tumor exosomes taken up by macrophages. We also showed that the tumor-promoting function of miR‑940 is mediated by TAM polarization in EOC. These findings show that tumor-derived exosomal miR‑940 induced by hypoxia plays an important role in stimulating TAM polarization in the progression of EOC.
A color change: X‐ray‐induced photochromic species are rare and can be used for detection of X‐rays. A highly robust X‐ray‐sensitive material with the discrete structure of a metal–organic complex ...has been found to show both soft and hard X‐ray‐induced photochromism at room temperature (see picture). A new ligand‐to‐ligand electron‐transfer mechanism was proposed to elucidate this photochromic phenomenon.
Epidermal growth factor receptor (EGFR) is a tyrosine kinase receptor involved in homeostatic regulation of normal cells and carcinogenesis of epithelial malignancies. With rapid development of the ...precision medicine era, a series of new therapies targeting EGFR are underway. Four EGFR monoclonal antibody drugs (cetuximab, panitumumab, nimotuzumab, and necitumumab) are already on the market, and a dozen other EGFR monoclonal antibodies are in clinical trials. Here, we comprehensively review the newly identified biological properties and anti-tumor mechanisms of EGFR monoclonal antibodies. We summarize recently completed and ongoing clinical trials of the classic and new EGFR monoclonal antibodies. More importantly, according to our new standard, we re-classify the complex evolving tumor cell resistance mechanisms, including those involving exosomes, non-coding RNA and the tumor microenvironment, against EGFR monoclonal antibodies. Finally, we analyzed the limitations of EGFR monoclonal antibody therapy, and discussed the current strategies overcoming EGFR related drug resistance. This review will help us better understand the latest battles between EGFR monoclonal antibodies and resistant tumor cells, and the future directions to develop anti-tumor EGFR monoclonal antibodies with durable effects.
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