Benzo[b]naphtho[1,2-d]thiophene Sulfoxides: Biomimetic Synthesis, Photophysical Properties, and Applications.

A practical synthesis of nonsymmetrical thiophene-fused aromatic systems has been developed that was inspired by the biodegradation of benzothiophene. For the first time, the photophysical properties of a series of π-conjugated benzo[b]naphtho[1,2-d]thiophene (BNT) sulfoxides were explored both in solution and in the solid state. The excellent fluorescence characteristics enable various applications of these compounds.

Differential Transcription and Alternative Splicing in Cotton Underly Specialized Defense Responses Against Pests.

The green mirid bug (Apolygus lucorum) and the cotton bollworm (Helicoverpa armigera) are both preferred to live on cotton but cause different symptoms, suggesting specialized responses of cotton to the two insects. In this study, we investigated differential molecular mechanisms underlying cotton plant defenses against A. lucorum and H. armigera via transcriptomic analyses. At the transcription level, jasmonate (JA) signaling was dominated in defense against H. armigera whereas salicylic acid (SA) signaling was more significant in defense against A. lucorum. A set of pathogenesis-related (PR) genes and protease inhibitor genes were differentially induced by the two insects. Insect infestations also had an impact on alternative splicing (AS), which was altered more significantly by the H. armigera than A. lucorum. Interestingly, most differential AS (DAS) genes had no obvious change at the transcription level. GO analysis revealed that biological process termed "RNA splicing" and "cellular response to abiotic stimulus" were enriched only in DAS genes from the H. armigera infested samples. Furthermore, insect infestations induced the retained intron of GhJAZs transcripts, which produced a truncated protein lacking the intact Jas motif. Taken together, our data demonstrate that the specialized cotton response to different insects is regulated by gene transcription and AS as well.

Slowing Development Facilitates Arabidopsis mgt Mutants to Accumulate Enough Magnesium for Pollen Formation and Fertility Restoration.

Magnesium (Mg) is an abundant and important cation in cells. Plants rely on Mg transporters to take up Mg from the soil, and then Mg is transported to anthers and other organs. Here, we showed that MGT6+/- plants display reduced fertility, while mgt6 plants are fertile. MGT6 is expressed in the anther at the early stages. Pollen mitosis and intine formation are impaired in aborted pollen grains (PGs) of MGT6+/- plants, which is similar to the defective pollen observed in mgt5 and mgt9 mutants. These results suggest that Mg deficiency leads to pollen abortion in MGT6+/- plants. Our data showed that mgt6 organs including buds develop significantly slower and mgt6 stamens accumulate a higher level of Mg, compared with wild-type (WT) and MGT6+/- plants. These results indicate that slower bud development allows mgt6 to accumulate sufficient amounts of Mg in the pollen, explaining why mgt6 is fertile. Furthermore, we found that mgt6 can restore fertility of mgt5, which has been reported to be male sterile due to defects in Mg transport from the tapetum to microspores and that an additional Mg supply can restore its fertility. Interestingly, mgt5 fertility is recovered when grown under short photoperiod conditions, which is a well-known factor regulating plant fertility. Taken together, these results demonstrate that slow development is a general mechanism to restore mgts fertility, which allows other redundant magnesium transporter (MGT) members to transport sufficient Mg for pollen formation.

Microwave-Assisted Synthesis of Heterocycles by Rhodium(III)-Catalyzed Annulation of N-Methoxyamides with α-Chloroaldehydes.

α-Chloroaldehydes have been used as alkyne equivalents in rhodium-catalyzed syntheses of isoquinolones and 3,4-dihydroisoquinolins starting from N-methoxyamides. Compared to the existing technology, a complementary regioselectivity is achieved. Mechanistic investigations have been performed, and it was found that steric effects of both substrate and additive determine the product selectivity. Various other heterocycles, such as isoquinolines and lactones, can be prepared by transformation of the obtained products.

The rice TCD11 encoding plastid ribosomal protein S6 is essential for chloroplast development at low temperature.

Plastid ribosome proteins (PRPs) are important components for chloroplast biogenesis and early chloroplast development. Although it has been known that chloroplast ribosomes are similar to bacterial ones, the precise molecular function of ribosomal proteins remains to be elucidated in rice. Here, we identified a novel rice mutant, designated tcd11 (thermo-sensitive chlorophyll-deficient mutant 11), characterized by the albino phenotype until it died at 20°C, while displaying normal phenotype at 32°C. The alteration of leaf color in tcd11 mutants was aligned with chlorophyll (Chl) content and chloroplast development. The map-based cloning and molecular complementation showed that TCD11 encodes the ribosomal small subunit protein S6 in chloroplasts (RPS6). TCD11 was abundantly expressed in leaves, suggesting its different expressions in tissues. In addition, the disruption of TCD11 greatly reduced the transcript levels of certain chloroplasts-associated genes and prevented the assembly of ribosome in chloroplasts at low temperature (20°C), whereas they recovered to nearly normal levels at high temperature (32°C). Thus, our data indicate that TCD11 plays an important role in chloroplast development at low temperature. Upon our knowledge, the observations from this study provide a first glimpse into the importance of RPS6 function in rice chloroplast development.

Formal (4+1) Cycloaddition and Enantioselective Michael-Henry Cascade Reactions To Synthesize Spiro[4,5]decanes and Spirooxindole Polycycles.

Spiro[4,5]decanes and polycyclic compounds bearing spiro[4,5]decane systems are important biofunctional molecules. Described are diastereoselective formal (4+1) cycloaddition reactions to afford oxindole-functionalized spiro[4,5]decanes and organocatalytic enantioselective Michael-Henry cascade reactions of the (4+1) cycloaddition products to generate spirooxindole polycyclic derivatives bearing the spiro[4,5]decane system. Spiro[4,5]decanes bearing oxindoles containing three stereogenic centers and spirooxindole polycycles having seven stereogenic centers, including two all-carbon chiral quaternary centers and one tetrasubstituted chiral carbon center, were obtained with high diastereo- and enantioselectivities.

Ginsenoside Rg1 and platelet-rich fibrin enhance human breast adipose-derived stem cell function for soft tissue regeneration.

Adipose-derived stem cells (ASCs) can be used to repair soft tissue defects, wounds, burns, and scars and to regenerate various damaged tissues. The cell differentiation capacity of ASCs is crucial for engineered adipose tissue regeneration in reconstructive and plastic surgery. We previously reported that ginsenoside Rg1 (G-Rg1 or Rg1) promotes proliferation and differentiation of ASCs in vitro and in vivio. Here we show that both G-Rg1 and platelet-rich fibrin (PRF) improve the proliferation, differentiation, and soft tissue regeneration capacity of human breast adipose-derived stem cells (HBASCs) on collagen type I sponge scaffolds in vitro and in vivo. Three months after transplantation, tissue wet weight, adipocyte number, intracellular lipid, microvessel density, and gene and protein expression of VEGF, HIF-1α, and PPARγ were higher in both G-Rg1- and PRF-treated HBASCs than in control grafts. More extensive new adipose tissue formation was evident after treatment with G-Rg1 or PRF. In summary, G-Rg1 and/or PRF co-administration improves the function of HBASCs for soft tissue regeneration engineering.

Multi-site cyclization via initial C-H activation using a rhodium(III) catalyst: rapid assembly of frameworks containing indoles and indolines.

Tandem multi-site cyclization triggered by Rh(iii)-catalyzed C-H activation has been achieved for highly efficient synthesis of spirocycle indolin-3-one (C2-cyclization), benzo[a]carbazole (C3-cyclization) and an unusual indoxyl core (N1-cyclization). In particular, the synthesis of pseudo-indoxyl is typically completed within 10 min, and the reaction tolerates air, water and a range of solvents.

Rhodium(III)-catalyzed three-component reaction of imines, alkynes, and aldehydes through C-H activation.

An efficient rhodium(III)-catalyzed tandem three-component reaction of imines, alkynes and aldehydes through CH activation has been developed. High stereo- and regioselectivity, as well as good yields were obtained in most cases. The simple and atom-economical approach offers a broad scope of substrates, providing polycyclic skeletons with potential biological properties.

Highly functionalized pyridines synthesis from N-sulfonyl ketimines and alkynes using the N-S bond as an internal oxidant.

The N-S bond-based internal oxidant offers a distinct approach for the synthesis of highly functionalized pyridines. A novel Rh(III)-catalyzed one-pot process undergoes an efficient C-C/C-N bond formation along with desulfonylation under very mild conditions. The method is quite simple, general, and efficient.

Rhodium(III)-catalyzed vinylic sp2 C-H bond functionalization: efficient synthesis of pyrido[1,2-α]benzimidazoles and imidazo[1,2-α]pyridines.

A simple approach for synthesis of novel aza-fused scaffolds such as pyrido[1,2-α]benzimidazoles and imidazo[1,2-α]pyridines was developed by Rh(III)-catalyzed direct oxidative coupling between alkenes and unactivated alkynes without an extra directing group. The method would allow a broad substrate scope, providing fused heterocycles with potential biological properties.

Rhodium(III)-catalyzed direct selective C(5)-H oxidative annulations of 2-substituted imidazoles and alkynes by double C-H activation.

Double C-H activations of C(5)-H and Csp(2)-H of 2-substituted N-vinyl- or arylimidazoles were realized without heteroatom-directing assistance by rhodium(III) catalyst. A subsequent oxidative annulation reaction with alkynes efficiently produced aza-fused heterocycles with high molecular complexity in low to excellent yields.

Synthesis of aza-fused polycyclic quinolines via double C-H bond activation.

Simple but efficient: Aza-fused polycyclic quinolines were efficiently assembled through rhodium(III)-based direct double C-H activation of N-aryl azoles followed by cyclization with alkynes without heteroatom-assisted chelation. Copper(II) acetate, aside from acting as an oxidant, could also play an important role in the C-H activation process.

Arabidopsis TT19 functions as a carrier to transport anthocyanin from the cytosol to tonoplasts.

Anthocyanins are synthesized in the cytosolic surface of the endoplasmic reticulum (ER) but dominantly accumulate in the vacuole. Little is known about how anthocyanins are transported from the ER to the vacuole. Here, we provide evidence supporting that Transparent Testa 19 (TT19), a glutathione S-transferase (GST), functions as a carrier to transport cyanidin and/or anthocyanins to the tonoplast. We identified a novel tt19 mutant (tt19-7), which barely accumulates anthocyanins but produces a 36% higher level of flavonol than the wild-type (WT), from ethyl methanesulfonate mutagenized seeds. Expressing TT19-fused green fluorescence protein (GFP) in tt19-7 rescues the mutant phenotype in defective anthocyanin biosynthesis, indicating that TT19-GFP is functional. We further showed that TT19-GFP is localized not only in the cytoplasm and nuclei, but also on the tonoplast. The membrane localization of TT19-GFP was further ascertained by immunoblot analysis. In vitro assay showed that the purified recombinant TT19 increases water solubility of cyanidin (Cya) and cyanidin-3-O-glycoside (C3G). Compared with C3G, Cya can dramatically quench the intrinsic tryptophan fluorescence of TT19 to much lower levels, indicating a higher affinity of TT19 to Cya than to C3G. Isothermal titration calorimetry analysis also confirmed physical interaction between TT19 and C3G. Taken together, our data reveal molecular mechanism underlying TT19-mediated anthocyanin transportation.

Organocatalytic chemoselective asymmetric N-allylic alkylation of enamides.

The first Lewis base-catalysed chemoselective asymmetric N-allylic alkylation of enamides with Morita-Baylis-Hillman carbonates has been developed, which affords multifunctional products in moderate to high enantioselectivity (up to 92% ee).

Direct asymmetric allylic alkylation of butenolides with Morita-Baylis-Hillman carbonates.

The direct asymmetric allylic alkylation of beta,gamma-butenolides with MBH carbonates to access gamma,gamma-disubstituted butenolides containing adjacent quaternary and tertiary chiral centers has been presented in excellent stereoselectivities (86-96% ee, dr >95:5) and moderate to good yield (50-83%). Their synthetic utility has been well demonstrated by the facile construction of bicyclic lactones bearing 4-5 stereogenic centers.

Cryptochromes, phytochromes, and COP1 regulate light-controlled stomatal development in Arabidopsis.

In Arabidopsis thaliana, the cryptochrome (CRY) blue light photoreceptors and the phytochrome (phy) red/far-red light photoreceptors mediate a variety of light responses. COP1, a RING motif-containing E3 ubiquitin ligase, acts as a key repressor of photomorphogenesis. Production of stomata, which mediate gas and water vapor exchange between plants and their environment, is regulated by light and involves phyB and COP1. Here, we show that, in the loss-of-function mutants of CRY and phyB, stomatal development is inhibited under blue and red light, respectively. In the loss-of-function mutant of phyA, stomata are barely developed under far-red light. Strikingly, in the loss-of-function mutant of either COP1 or YDA, a mitogen-activated protein kinase kinase kinase, mature stomata are developed constitutively and produced in clusters in both light and darkness. CRY, phyA, and phyB act additively to promote stomatal development. COP1 acts genetically downstream of CRY, phyA, and phyB and in parallel with the leucine-rich repeat receptor-like protein TOO MANY MOUTHS but upstream of YDA and the three basic helix-loop-helix proteins SPEECHLESS, MUTE, and FAMA, respectively. These findings suggest that light-controlled stomatal development is likely mediated through a crosstalk between the cryptochrome-phytochrome-COP1 signaling system and the mitogen-activated protein kinase signaling pathway.