Antibacterial Mechanism of Shikonin Against Vibrio vulnificus and Its Healing Potential on Infected Mice with Full-Thickness Excised Skin.

Shikonin has anticancer, anti-inflammatory, and wound healing activities. Vibrio vulnificus is an important marine foodborne pathogen with a high fatality rate and rapid pathogenesis that can infect humans through ingestion and wounds. In this study, the antibacterial activity and possible antibacterial mechanism of shikonin against V. vulnificus were investigated. In addition, the ability of shikonin to control V. vulnificus infection in both pathways was assessed by artificially contaminated oysters and full-thickness excised skin-infected mice. Shikonin treatment can cause abnormal cell membrane function, as evidenced by hyperpolarization of the cell membrane, significant decreased intracellular ATP concentration (p < 0.05), significant increased intracellular reactive oxygen species and malondialdehyde content (p < 0.05), decreased cell membrane integrity, and changes in cell morphology. Shikonin at 40 and 80 µg/mL reduced bacterial numbers in shikonin-contaminated oysters by 3.58 and 2.18 log colony-forming unit (CFU)/mL. Shikonin can promote wound healing in mice infected with V. vulnificus by promoting the formation of granulation tissue, hair follicles, and sebaceous glands, promoting epithelial cell regeneration and epidermal growth factor production. These findings suggest that shikonin has a strong inactivation effect on V. vulnificus and can be used in food production and wound healing to effectively control V. vulnificus and reduce the number of diseases associated with it.

Chromosome-level assembly of the Neolamarckia cadamba genome provides insights into the evolution of cadambine biosynthesis.

Neolamarckia cadamba (Roxb.), a close relative of Coffea canephora and Ophiorrhiza pumila, is an important traditional medicine in Southeast Asia. Three major glycosidic monoterpenoid indole alkaloids (MIAs), cadambine and its derivatives 3ß-isodihydrocadambine and 3ß-dihydrocadambine, accumulate in the bark and leaves, and exhibit antimalarial, antiproliferative, antioxidant, anticancer and anti-inflammatory activities. Here, we report a chromosome-scale N. cadamba genome, with 744.5 Mb assembled into 22 pseudochromosomes with contig N50 and scaffold N50 of 824.14 Kb and 29.20 Mb, respectively. Comparative genomic analysis of N. cadamba with Co. canephora revealed that N. cadamba underwent a relatively recent whole-genome duplication (WGD) event after diverging from Co. canephora, which contributed to the evolution of the MIA biosynthetic pathway. We determined the key intermediates of the cadambine biosynthetic pathway and further showed that NcSTR1 catalyzed the synthesis of strictosidine in N. cadamba. A new component, epoxystrictosidine (C27H34N2O10, m/z 547.2285), was identified in the cadambine biosynthetic pathway. Combining genome-wide association study (GWAS), population analysis, multi-omics analysis and metabolic gene cluster prediction, this study will shed light on the evolution of MIA biosynthetic pathway genes. This N. cadamba reference sequence will accelerate the understanding of the evolutionary history of specific metabolic pathways and facilitate the development of tools for enhancing bioactive productivity by metabolic engineering in microbes or by molecular breeding in plants.

Ring-tension adjusted ethylene polymerization by aryliminocycloheptapyridyl nickel complexes.

The stoichiometric reactions of 5,6,7,8-tetrahydrocycloheptapyridin-9-one (cycloheptapyridin-9-one) with various anilines lead to corresponding mixtures of 9-aryliminocycloheptapyridine and the isomeric 9-arylamino-5,6,7-trihydrocycloheptapyridine derivatives; these compounds further reacted with nickel dichloride to form 9-aryliminocycloheptapyridyl nickel chlorides, respectively. The new organic compounds were analyzed by the NMR measurements, and all the organic and complex compounds were characterized by the FT-IR spectroscopy and elemental analysis. In addition, the molecular structures of representative nickel complexes and , determined by means of single-crystal X-ray diffraction, were found to be binuclear dimers with distorted square-pyramidal geometry around the nickel centers. On activation with either ethylaluminium sesquichloride (Et3Al2Cl3) or methylaluminoxane (MAO), all nickel complex pre-catalysts exhibited high activities of up to 7.80 × 10(6) g PE mol(-1) (Ni) h(-1) toward ethylene polymerization and produced highly branched polyethylenes in narrow polydispersity. The title nickel complexes showed comparable activities with 8-arylimino-5,6,7-trihydroquinolyl nickel analogues; whilst both exhibited higher activities than did the 2-iminopyridyl nickel analogues due to the enhancement of the ring-tension of cyclic-fused pyridine derivatives.

2-(1-Aryliminoethyl)-9-arylimino-5,6,7,8-tetrahydrocycloheptapyridyl iron(II) dichloride: synthesis, characterization, and the highly active and tunable active species in ethylene polymerization.

A series of 2-(1-arylimino)ethyl-9-arylimino-5,6,7,8-tetrahydrocycloheptapyridine derivatives was synthesized and fully characterized, and thereafter reacted with iron dichloride to form their corresponding iron(II) complexes. The single crystals of representative organic and iron complex compounds were obtained and analyzed by the X-ray diffraction analysis, indicating the distorted bipyramidal geometry around the iron core. Moreover, DFT calculations were performed on selected species to determine their structural features. On treatment with either MAO or MMAO, all iron complex pre-catalysts showed high activities (up to 1.56 × 10(7) gPE mol(-1)(Fe) h(-1)) toward ethylene polymerization. Regarding the nature of the ligands and reaction parameters, their catalytic activities and the characters of the obtained polyethylenes have been carefully investigated. The ring strain of the fused-cycloheptane of the ligands within iron complexes was considered to affect their catalytic performance in ethylene polymerization. The active species were activated and controlled by using a co-catalyst of MMAO preferred over MAO, and the obtained polyethylenes with MMAO showed narrower molecular polydispersity than the corresponding polyethylenes with MAO.