Designable Photo-Responsive Micron-Scale Ultrathin Peptoid Nanobelts for Enhanced Performance on Hydrogen Evolution Reaction.

The development of high-reactive single-atom catalysts (SACs) based on long-range-ordered ultrathin organic nanomaterials (UTONMs) (i.e., below 3 nm) provides a significant tactic for the advancement in hydrogen evolution reactions (HER) but remains challenging. Herein, photo-responsive ultrathin peptoid nanobelts (UTPNBs) with a thickness of ≈2.2 nm and micron-scaled length are generated using the self-assembly of azobenzene-containing amphiphilic ternary alternating peptoids. The pendants hydrophobic conjugate stacking mechanism reveals the formation of 1D ultralong UTPNBs, whose thickness is dictated by the length of side groups that are linked to peptoid backbones. The photo-responsive feature is demonstrated by a reversible morphological transformation from UTPNBs to nanospheres (21.5 nm) upon alternative irradiation with UV and visible lights. Furthermore, the electrocatalyst performance of these aggregates co-decorated with nitrogen-rich ligand of terpyridine (TE) and uniformly-distributed atomic platinum (Pt) is evaluated toward HER, with a photo-controllable electrocatalyst activity that highly depended on both the presence of Pt element and structural characteristic of substrates. The Pt-based SACs using TE-modified UTPNBs as support exhibit a favorable electrocatalytic capacity with an overpotential of ≈28 mV at a current density of 10 mA cm-2. This work presents a promising strategy to fabricate stimuli-responsive UTONMs-based catalysts with controllable HER catalytic performance.

Antibacterial Polyketides from Antarctica Sponge-Derived Fungus Penicillium sp. HDN151272.

Three new polyketides, ketidocillinones A-C (1-3), were discovered from the extract of an Antarctica sponge-derived fungus Penicillium sp. HDN151272. All the structures were deduced by spectroscopic data, including NMR and HRESIMS. The absolute configuration of compound 3 was established by using ECD calculation. Compounds 1-3 can be slowly oxidized to quinone form when exposed to air. Ketidocillinones B and C (2 and 3) exhibited potent antibacterial activity against Pseudomonas aeurigenosa, Mycobacterium phlei, and MRCNS (methicillin-resistant coagulase-negative staphylococci) with MIC values ranging from 1.56 to 25.00 µg/mL.

Secondary Metabolites Produced by Combined Culture of Penicillium crustosum and a Xylaria sp.

Four new alkyl aromatics, penixylarins A-D (1-4), along with the known biogenetically related 1,3-dihydroxy-5-(12-hydroxyheptadecyl)benzene (5) and 1,3-dihydroxy-5-(12-sulfoxyheptadecyl)benzene (6), were isolated from a mixed culture of the Antarctic deep-sea-derived fungus Penicillium crustosum PRB-2 and the mangrove-derived fungus Xylaria sp. HDN13-249. UPLC-MS data and an analysis of structural features showed that compounds 1 and 2 were produced by collaboration of the two fungi, while compounds 3-6 could be produced by Xylaria sp. HDN13-249 alone, but in noticeably increased quantities by cocultivation. Compounds 2, 3, 5, and 6 showed antibacterial activity against a panel of strains, and compound 3 possessed potential antituberculosis effects (MIC = 6.25 µM against Mycobacterium phlei).

Cytotoxic Tetrahydroxanthone Dimers from the Mangrove-Associated Fungus Aspergillus versicolor HDN1009.

Three new tetrahydroxanthone dimers, 5-epi-asperdichrome (1), versixanthones N (2), and O (3), were isolated from the mangrove-derived fungus Aspergillus versicolor HDN1009. Their structures, including the absolute configurations, were elucidated by NMR, HRMS, and circular dichroism (CD) experiments. Among them, compound 1 was the second example of tetrahydroxanthone dimers, which dimerized by a rare diaryl ether linkage and showed promising antibacterial activities against Vibrio parahemolyticus, Bacillus subtilis, Mycobacterium phlei, and Pseudomonas aeruginosa, with MIC values ranging from 100 µM to 200 µM; whilst compounds 2 and 3 exhibited extensive cytotoxicities against five cancer cell lines (HL-60, K562, H1975, MGC803, and HO-8910), with IC50 values ranging from 1.7 µM to 16.1 µM.

Comparative genomics and evolutionary analyses of the O-methyltransferase gene family in Populus.

S-adenosyl-l-methionine (SAM) dependent O-methyltransferases (OMTs) proteins are involved in the methylation of various secondary metabolites. The OMT genes have been studied in various plants, but these studies focused either on a single or a small set of genes. Moreover, no comprehensive study was published yet on the OMT gene family in a tree species. To investigate the evolutionary history of this gene family and the functional diversification of its members, phylogenetic and several comparative genomics analyses were performed. Phylogeny across land plant lineages showed that OMT genes were distributed in two main classes deeply rooted in the phylogeny of land plants, suggesting that they have evolved by a gene duplication that had happen in the ancestor of land plants. COMT and COMT-like genes were clustering with few flavonoid and multifunctional OMT genes in class II. Class I included flavonoid, simple phenol, and multifunctional OMT genes. All 26 Populus OMT genes were located in segmental duplication blocks and two third of them were tandem duplicated, indicating the role of duplication processes in the expansion of this gene family. Expression profiling of OMT genes in Populus showed that only PoptrOMT25 was differentially expressed in xylem. The other genes were differentially expressed in leaves, bark, or both. Some OMT genes showed differential expression patterns under various biotic and abiotic stresses. The divergence of protein sequences, the phylogenetic distribution, and the expression of COMT and COMT-like genes suggest that they have evolved different functions or tissue specificities following duplications.