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A new palladium(II) complex based on N,N-dimethylethanolamine, (SP-4-1')-bis[N,N-dimethylaminoethoxy-kN,O]palladium( II) which coordinates with two moles of AcOH, has been synthesized. The structure of the complex has been established by X-ray diffraction analysis. Using this complex as a catalyst, a series of conjugated enynes were successfully synthesized by Sonogashira cross-coupling reaction in the absence of co-catalyst CuX and any ligand at room temperature during 20 hours affording the corresponding products in moderate to excellent yields. The optimized catalytic systems are tolerant in the presence of a broad variety of functional groups in the substrates. The catalytic system was found to be ineffective for vinyl chloride. Moreover, it was found that (Z)- β-bromostyrene reacts with terminal alkynes with retention of the steric configuration and the transformation of most of the Z-isomer did not occur in this reaction. [ABSTRACT FROM AUTHOR]

Infections by many bacterial pathogens rely on their ability to degrade host glycans by producing glycoside hydrolases (GHs). Here, we discovered a conserved multifunctional GH, SsGal-NagA, containing a unique combination of two family 32 carbohydrate-binding modules (CBM), a GH16 domain and a GH20 domain, in the zoonotic pathogen Streptococcus suis 05ZYH33. Enzymatic assays revealed that the SsCBM-GH16 domain displays endo-(β1,4)-galactosidase activity specifically toward the host-derived aGal epitope Gal(a1,3)Gal(b1,4)Glc(NAc)-R, whereas the SsGH20 domain has a wide spectrum of exo-β-Nacetylhexosaminidase activities, including exo-(β1,3)-N-acetylglucosaminidase activity, and employs this activity to act in tandem with SsCBM-GH16 on the αGal-epitope glycan. Further, we found that the CBM32 domain adjacent to the SsGH16 domain is indispensable for SsGH16 catalytic activity. Surface plasmon resonance experiments uncovered that both CBM32 domains specifically bind to αGal-epitope glycan, and together they had a KD of 3.5mM toward a pentasaccharide αGal-epitope glycan. Cell-binding and αGal epitope removal assays revealed that SsGalNagA efficiently binds to both swine erythrocytes and tracheal epithelial cells and removes the aGal epitope from these cells, suggesting that SsGalNagA functions in nutrient acquisition or alters host signaling in S. suis. Both binding and removal activities were blocked by an αGal-epitope glycan. SsGalNagA is the first enzyme reported to sequentially act on a glycan containing the αGal epitope. These findings shed detailed light on the evolution of GHs and an important hostpathogen interaction. [ABSTRACT FROM AUTHOR]

The immune signaling pathway mediated by Dectin-1 is important in mammals to modulate the production of IL-17 and TNF-α. Recently, IL-17 and TNF have also been characterized in invertebrates to play crucial roles in antibacterial immune responses, although the immune recognition and regulation mechanisms to produce IL-17 and TNF are still not well investigated. In the current study, a novel C-type lectin receptor (named CgCLec-HTM) with a signal peptide, a carbohydrate recognition domain, a transmembrane domain, and a nonclassical ITAM (hemITAM) in the cytoplasmic tail was identified from oyster Crassostrea gigas. CgCLec-HTM could bind LPS and various bacteria. After binding to its ligands, CgCLec-HTM was associated with the Src homology 2 (SH2) domain of spleen tyrosine kinase (CgSyk) by the hemITAM in its cytoplasmic tail to promote ERK (CgERK) phosphorylation. The activated CgERK could interact with CgRel to induce CgRel nuclear translocation. The CgRel in the nucleus eventually induced the transcription of CgIL-17s and CgTNF. The results demonstrated that CgCLec-HTM with a broad binding spectrum of bacteria could be associated with CgSyk to transfer immune signals into the intracellular ERK-Rel pathway to induce CgIL-17 and CgTNF production. [ABSTRACT FROM AUTHOR]

[Display omitted] • High yield of o -CAN (more than 99.9%) was obtained. • No dechlorinated products was detected in the range of 50∼120 ℃. • No catalyst deactivation was observed in 200 h. • TOPM (12290) is superior to the values reported in the literatures (364∼9280). Solvent-free hydrogenation of chloronitrobenzene is considered as the most efficient and cleanest method for the production of chloroanilines which are important intermediates in the medicine, pigment and dye industry. However, it is difficult to suppress the side reaction of dechlorination in the solvent-free hydrogenation process. Herein, a novel Pt /amide group grafted AC catalyst was prepared by covalently grafting N-containing groups on commercial activated carbon which forms amide bond for solvent-free hydrogenation of chloronitrobenzene. Several Pt /amide group grafted AC catalysts grafted with different N-containing groups were prepared and experimental results indicate that Pt /amide group grafted AC catalysts covalently grafted with 1,3-cyclohexanediamine exhibit excellent performance on the suppression of dechlorination. The characterization results reveal that Pt/C catalyst grafted with 1,3-cyclohexanediamine has a narrower particle size distribution and smaller average size in comparison with Pt/C. The catalyst was evaluated in the solvent-free continuous hydrogenation of o -CNB to o -CAN and no dechorinated products was detected and high yield of o -CAN (more than 99.9%) was obtained in the range of 50∼120 ℃ compared with the severe dechlorination using Pt/C catalyst (yield of dechlorinated products≥70%). Additionally, no catalyst deactivation was observed in 200 h and turnover number per mole active metal (12290) is higher than the catalysts reported in the literatures (364∼9280) exhibiting the remarkable stability of Pt/C-N catalyst. [ABSTRACT FROM AUTHOR]

A new and efficient metal-free tandem acylation/cyclization of alkynoates with aldehydes was developed for the synthesis of 3-acyl-4-arylcoumarins. The reaction was achieved by the addition of acyl radical to alkynes and a C-H bond functionalization to form two new C-C bonds simultaneously. [ABSTRACT FROM AUTHOR]

Designer transcription-activator like effectors (TALEs) is a promising technology and made it possible to edit genomes with higher specificity. Such specific engineering and gene regulation technologies are also being developed using RNA-binding proteins like PUFs and PPRs. The main feature of TALEs, PUFs and PPRs is their repetitive DNA/RNA-binding domains which have single nucleotide binding specificity. Available kits today allow researchers to assemble these repetitive domains in any combination they desire when generating TALEs for gene targeting and editing. However, PCR amplifications of such repetitive DNAs are highly problematic as these mostly fail, generating undesired artifact products or deletions. Here we describe the molecular mechanisms leading to these artifacts. We tested our models also in plasmid templates containing one copy versus two copies of GFP-coding sequence arranged as either direct or inverted repeats. Some limited solutions in amplifying repetitive DNA regions are described. [ABSTRACT FROM AUTHOR]

An efficient phosphine-free direct C-H arylation of thiophenes at the α-position has been developed at low catalyst loading of bis(alkoxo)palladium complex (Cat.I, 0.1-0.2 mol %). The developed synthetic method can be applied to the synthesis of α-aryl/heteroaryl thiophenes from aryl or heteroaryl bromides in good to excellent yields and is compatible with the substrates bearing electron-donating or electron-withdrawing groups. The reactivities of the 2- and 5-positions of thiophenes are equivalent and not dependent on steric hindrance under optimal conditions. This condition can also be applied to other heterocyclic moieties such as benzothiophene, benzofuran, and pyrrole with high conversion yields. [ABSTRACT FROM AUTHOR]

Background: As one of the most popular expression systems, recombinant protein expression in Pichia pastoris relies on the AOX1 promoter (PAOX1) which is strongly induced by methanol. However, the toxic and inflammatory nature of methanol restricts its application, especially in edible and medical products. Therefore, constructing a novel methanol-free system becomes necessary. The kinases involved in PAOX1 activation or repression by different carbon sources may be promising targets. Results: We identified two kinase mutants: Δgut1 and Δdak, both of which showed strong alcohol oxidase activity under non-methanol carbon sources. Based on these two kinases, we constructed two methanol-free expression systems: Δgut1-HpGCY1-glycerol (PAOX1 induced by glycerol) and Δdak-DHA (PAOX1 induced by DHA). By comparing their GFP expression efficiencies, the latter one showed better potential. To further test the Δdak-DHA system, three more recombinant proteins were expressed as examples. We found that the expression ability of our novel methanol-free Δdak-DHA system was generally better than the constitutive GAP promoter, and reached 50-60 % of the traditional methanol induced system. Conclusions: We successfully constructed a novel methanol-free expression system Δdak-DHA. This modified expression platform preserved the favorable regulatable nature of PAOX1, providing a potential alternative to the traditional system. [ABSTRACT FROM AUTHOR]

With high regioselectivity, a series of benzoheterocyclic compounds were synthesized via palladiium-catalyzed phosphine-free C–H arylation of benzothiophenes/benzofurans with aryl MIDA boronates at 30-50 °C in moderate to excellent yields. MIDA boronates were used in C–H arylation of heterocycles for the first time. Under the optimal conditions, the benzothiophenes could be transformed into the β-arylbenzothiophenes, and the benzofurans gave only α-aryl-substituted products. [ABSTRACT FROM AUTHOR]

A novel and efficient method for the synthesis of α-cyanomethyl-β-dicarbonyls in moderate to excellent yields is developed by using inactive CH3CN and simple 1,3-dicarbonyls. A radical mechanism is proposed under the ESI-MS (electrospray ionization mass spectrometry) analysis results of control experiments. [ABSTRACT FROM AUTHOR]

The aim of this study is to demonstrate the enhanced herapeutic efficacy of anticancer drugs on drug-resistant breast cancer using multicomponent microemulsions (ECG-MEs) as an oral delivery system. The etoposide-loaded ECG-MEs were composed of coix seed oil and ginsenoside Rh2 (G-Rh2), both of which possess not only the synergistic antitumor effect with etoposide, but also have excipient-like properties. Orally administrated ECG-MEs were demonstrated to be able to accumulate at the tumor site following crossing the intestines as intact vehicles into the blood circulation. The spatiotemporal controlled release characteristics of ECG-MEs brought about the efficient P-gp inhibition by the initially released G-Rh2 and the increased intracellular accumulation of the sequentially released etoposide. The combination antitumor activity of etoposide, G-Rh2 and coix seed oil using ECG-MEs was verified on the xenograft drug-resistant breast tumor mouse models. In addition, the safety evaluation studies indicated that treatment with ECG-MEs did not cause any significant toxicity in vivo. These findings suggest that ECG-MEs as an oral formulation may offer a promising strategy to treat the drug-resistant breast cancer. [ABSTRACT FROM AUTHOR]