Despite the widespread adoption of communicative language teaching (CLT) in ESL countries, research suggests that curricular innovations prompted by the adoption of CLT in EFL countries have generally been difficult. The literature on curriculum innovation suggests that teachers' understanding of an innovation is central to its success. A study of a group of South Korean secondary school English teachers' perceived difficulties in adopting CLT reveals that the difficulties have their source in the differences between the underlying educational theories of South Korea and those of Western countries. The results suggest that, to adopt CLT, EFL countries like South Korea will need to change their fundamental approach to education and that implementation should be gradual and grounded in the countries' own EFL situations. In the long run, EFL countries should establish their own contingent of language researchers in order to develop English teaching theories more suitable for their EFL contexts. Change agents must study teachers' perceptions of an innovation to ensure its success.

Polymyxins are the last line of defense against lethal infections caused by multidrug resistant Gram-negative pathogens. Very recently, the use of polymyxins has been greatly challenged by the emergence of the plasmid-borne mobile colistin resistance gene (mcr-1). However, the mechanistic aspects of the MCR-1 colistin resistance are still poorly understood. Here we report the comparative genomics of two new mcr-1-harbouring plasmids isolated from the human gut microbiota, highlighting the diversity in plasmid transfer of the mcr-1 gene. Further genetic dissection delineated that both the trans-membrane region and a substrate-binding motif are required for the MCR-1-mediated colistin resistance. The soluble form of the membrane protein MCR-1 was successfully prepared and verified. Phylogenetic analyses revealed that MCR-1 is highly homologous to its counterpart PEA lipid A transferase in Paenibacili, a known producer of polymyxins. The fact that the plasmid-borne MCR-1 is placed in a subclade neighboring the chromosome-encoded colistin-resistant Neisseria LptA (EptA) potentially implies parallel evolutionary paths for the two genes. In conclusion, our finding provids a first glimpse of mechanism for the MCR-1-mediated colistin resistance.

4-Coumaric acid:CoA ligase (4CL) is the central enzyme of the plant-specific phenylpropanoid pathway. It catalyzes the synthesis of hydroxycinnamate-CoA thioesters, the precursors of lignin and other important phenylpropanoids, in two-step reactions involving the formation of hydroxycinnamate-AMP anhydride and then the nucleophilic substitution of AMP by CoA. In this study, we determined the crystal structures of Populus tomentosa 4CL1 in the unmodified (apo) form and in forms complexed with AMP and adenosine 59-(3-(4-hydroxyphenyl)propyl)phosphate (APP), an intermediate analog, at 2.4, 2.5, and 1.9 Å resolution, respectively. 4CL1 consists of two globular domains connected by a flexible linker region. The larger N-domain contains a substrate binding pocket, while the C-domain contains catalytic residues. Upon binding of APP, the C-domain rotates 818 relative to the N-domain. The crystal structure of 4CL1-APP reveals its substrate binding pocket. We identified residues essential for catalytic activities (Lys-438, Gln-443, and Lys-523) and substrate binding (Tyr-236, Gly-306, Gly-331, Pro-337, and Val-338) based on their crystal structures and by means of mutagenesis and enzymatic activity studies. We also demonstrated that the size of the binding pocket is the most important factor in determining the substrate specificities of 4CL1. These findings shed light on the enzymatic mechanisms of 4CLs and provide a solid foundation for the bioengineering of these enzymes.

Betulin and betulinic acid have been widely studied for their anticancer activities. However, their further development is limited due to low bioavailability, poor aqueous solubility, and limited intracellular accumulation. In the present study, a triphenylphosphonium cation moiety was linked to betulin and betulinic acid to specifically target them to cancer cell mitochondria. Biological characterization established that uptake of mitochondria-targeted compound 1a in the mitochondria of cancer cells was increased compared to betulin. The mitochondria-targeted derivatives of betulin and betulinic acid showed stronger cytotoxicity than their parent drugs and exhibited more cytotoxic effects in cancer cells than normal cells. The mechanisms may involve the mitochondrial apoptotic pathway, probably caused by the induction of reactive oxygen species production and reducing mitochondrial membrane potential. More importantly, 1a significantly inhibited cancer cell proliferation and migration in an in vivo zebrafish xenograft model. Collectively, these results encourage further study of 1a analogs as anticancer agents.

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Highly ordered mesoporous silica materials are hydrothermally synthesized at high temperature by using fluorocarbon–hydrocarbon surfactant mixtures as templates. Because of the high temperature of the synthesis, the obtained materials show complete silica condensation, which give rise to ultra‐stabile structures. JLU‐20 for example (see TEM image of calcined JLU‐20) has a fully condensed mesopore wall with a very high Q4/Q3 ratio of 6.5.

Dietary fiber (DF) is increasingly thought to regulate diversity of piglet gut microbiota to alleviate weaning stress in piglets. This study was conducted to investigate the effects of DF on growth performance of piglets and composition of their gut microbiota, as well as the interaction between gut microbiota and short-chain fatty acids (SCFAs) in piglets. A total of 840 piglets were allocated to three dietary treatments consisting of a control group (CG), an alfalfa meal group (AG), and a commodity concentrated fiber group (OG) in a 30-day feeding trial. Gut mucosa and feces samples were used to determine bacterial community diversity by 16S rRNA gene amplicon sequencing. Fiber treatment had a positive effect on growth performance and metabolism of SCFAs in piglets, in particular, compared with CG, the diarrhea rate was significantly decreased, and the content of propionic acid (PA) in the cecum was markedly increased in AG. The Shannon indices of the jejunum microbiota in AG were higher than CG. At the genus level, compared to CG, in the duodenum, the relative abundance of Paenibacillus in AG and OG was higher; in the jejunum, the relative abundances of Bacillus, Oceanobacillus, Paenibacillus, Lactococcus, Enterococcus, and Exiguobacterium were higher, whereas the relative abundance of Mycoplasma was lower in AG; in the cecum, there was also lower relative abundance of Helicobacter in AG and OG, and furthermore, the relative abundance of Faecalibacterium in OG was higher than in CG and AG. Spearman correlation analysis showed that Pseudobutyrivibrio was positively correlated with acetic acid, PA, and butyric acid (BA), while Bacteroides and Anaerotruncus were negatively correlated with PA and BA. In addition, microbiota analyses among different intestine segments showed distinct differences in microbiota between the proximal and distal intestines. Bacteria in the proximal segments were mainly Firmicutes, while bacteria in the distal segments were mainly Bacteroidetes and Firmicutes. Overall, these findings suggested that DF treatment could reduce the diarrhea rate of piglets and had beneficial effects on gut health, which might be attributed to the alteration in gut microbiota induced by DF and the interaction of the gut microbiota with SCFAs.

Mesoporous pure silica (MPS-9) is prepared using an assembly of preformed Silicalite-I nanoclusters with a triblock copolymer surfactant. The results of X-ray diffraction, transmission electron microscopy, and N 2 adsorption show that MPS-9 has a mesostructure that is similar to that of other mesoporous materials prepared from preformed zeolite nanoclusters, such as mesoporous aluminum silicates (MAS-7, MAS-9) and titanium silicate (MTS-9). However, MPS-9 shows weaker hydrothermal stability, in comparison to those other mesoporous materials prepared from preformed zeolite nanoclusters. On the other hand, three Al-SBA-15 samples synthesized from various routes are all much more hydrothermally stable than pure silica SBA-15. The previously proposed factors, including thicker pore walls, a disordered structure, the "salt effect", and zeolite-like connectivity, have been proven to be indeed favorable for the improvement of hydrothermal stability in this study. However, the introduction of heteroatoms (Al or Ti) in mesoporous materials is another favorable factor and can enhance the hydrothermal stability to a greater extent.