Green synthesis of selenium/attapulgite nanocomposites and antibacterial activities evaluation

Se nanoparticles (NPs) with smaller size often exhibit higher antibacterial activity, thus size control of Se NPs is important to develop its application in the antibacterial field. In this study, Se NPs loaded attapulgite (APT) nanocomposites (Se/APT) were successfully prepared by a one-pot green method mediated by Aloe vera leaf extract, for which APT acts as a support to anchor Se NPs leading to the formation of small-sized and dispersed Se NPs. Structure characterization showed that the well-crystalline Se NPs with a size range of 1 ∼ 3 nm were uniformly distributed on the surface of APT nanorods. Antibacterial activities of the Se/APT nanocomposites were examined against S. aureus, and the result showed that the higher the Se loadings, the better the antibacterial activities of the nanocomposites, and the minimum inhibitory concentration of Se/APT-40% nanocomposite was up to 0.5 mg/mL. In addition, the green-synthesized nanocomposites have little cytotoxicity on mouse fibroblast cell L-929, and conversely promoted the growth and proliferation of the cells. The nanocomposites are expected to be candidates used in various antibacterial fields for preventing infections induced by S. aureus, such as suppuration of the wound

Efficient methoxycarbonylation of diisobutylene over functionalized ZSM-5 supported cobalt complex catalysts

By grafting nitrogen-containing complexes onto ZSM-5 mesoporous material and then supporting a cobalt catalyst in situ, the methoxycarbonylation of diisobutylene (DIB) was achieved. Moreover, a series of functionalized ZSM-5 mesoporous materials containing different nitrogen complexes were synthesized and characterized by FT-IR, N2 adsorption–desorption isotherms, XRD, SEM, and X-ray photoelectron spectroscopy (XPS). Subsequently, the catalytic activity of functionalized ZSM-5 mesoporous materials and the reaction parameters in the methoxycarbonylation of DIB were investigated. The results revealed that the conversion of DIB was 88.3% and the selectivity for methyl isononanoate was 93.4% under solvent-free conditions at 6.0 MPa and 140 °C for 10 h by using the catalyst ZSM-5iCPdPy@Co2(CO)8. The potential mechanism for this catalytic reaction was also put forth. Admittedly, these inexpensive and easy-to-recover heterogeneous catalysts can replace the noble metal palladium complexes on a laboratory scale to achieve partial olefin carbonylation reactions

Double-Oxidative Dehydrogenative (DOD) [4 + 2]-Cyclization/Oxidative Aromatization Tandem Reaction of Glycine Derivatives with Ethylbenzenes

The double-oxidative dehydrogenative (DOD) cyclization represents one of the most straightforward and atom-economical methods for cyclic structure formation. A Cu­(II)/DDQ/O₂ system-catalyzed DOD [4 + 2]-annulation/oxidative aromatization tandem reaction of readily available glycine derivatives and alkylbenzenes was established. This approach facilitates rapid access to a broad scope of substituted quinoline-2-carboxylate derivatives, an important motif in drug discovery. The reaction could feasibly be applied to a 10 gram-scale synthesis

Identification and characterization of a novel abiotic stress responsive OsTHIC gene from rice

To better understand the mechanisms of plant abiotic stress responses and identify novel stress-related genes in rice, we performed global expression analysis in indica rice Pei'ai 64S under multiple stresses. Among numerous genes, a gene named OsTHIC was selected, which was highly induced in leaves and panicles in response to all stresses at different developmental stages, especially at the booting stage under cold stress. OsTHIC contains an open reading frame (ORF) of 1920 bp and encodes a predicted protein with 639 amino acid residues. The molecular weight and isoelectric point were predicted to be about 71.31 kD and 6.41, respectively. The results of quantitative real-time polymerase chain reaction (qRT-PCR) analysis were almost identical to those from the GeneChip Rice Genome Array. The sequence alignment showed about 99% similarity to rice phosphate methylpyrimidine synthase. Promoter sequence analysis showed that various stress response-related cis-elements were contained in the promoter region. All the results suggested that OsTHIC may be involved in rice stress responses

Overexpression of a thylakoid membrane protein gene OsTMP14 improves indica rice cold tolerance

Cold has a major impact on rice, so rice can only grow in specific climate zones. TMP14 (thylakoid membrane protein of 14 kDa) is a nuclear genome-encoded chloroplast thylakoid membrane protein, which is involved in a wide range of abiotic stress responses. However, the knowledge of TMP14 roles in response to adverse stimuli is still very limited in rice. Based on the results of expression profiles, OsTMP14 (GenBank accession: BAF27084.1) was highly induced in both leaf and panicle at all the developmental stages of rice analyses under cold and drought stresses. Sequence analyses of OsTMP14 putative promoter regions identified nine cis-elements related to stress responses. Furthermore, transgenic rice plants with overexpression of OsTMP14 showed more tolerance to cold stress. Taken together, these results indicate that OsTMP14 is involved in stress tolerance in rice, which is useful in developing transgenic rice with enhancing tolerance to cold stress