Flowerlike CuO nanostructures were prepared by the coprecipitation method with postannealing in air at different temperatures. The results of X-ray diffraction and Raman and X-ray photoelectron spectroscopies show that the samples annealed at 400, 600, and 800 °C have a typical monoclinic structure and are absent of impurity phases. Magnetic measurements indicate that all of the CuO nanostructures show room-temperature ferromagnetism, whereas CuO bulk presents paramagnetism. The saturation magnetization of the samples was found to increase with increasing annealing temperature. The fitting results of the O 1s XPS spectra for the three samples indicate that oxygen vacancies exist in the samples and that the variation of the oxygen vacancy concentration is in complete agreement with the variation of the saturation magnetization. When the samples were annealed in oxygen atmosphere, the ferromagnetism of the samples decreased enormously. These results confirm that the observed room-temperature ferromagnetism in flowerlike CuO nanostructures might originate from oxygen vacancies.

Salinity is one of the major abiotic stresses that impacts plant growth and reduces the productivity of field crops. Compared to field plants, test tube plantlets offer a direct and fast approach to investigate the mechanism of salt tolerance. Here we examined the ultrastructural and physiological responses of potato (Solanum tuberosum L. c.v. “Longshu No. 3”) plantlets to gradient saline stress (0, 25, 50, 100, and 200 mM NaCl) with two consequent observations (2 and 6 weeks, respectively). The results showed that, with the increase of external NaCl concentration and the duration of treatments, (1) the number of chloroplasts and cell intercellular spaces markedly decreased, (2) cell walls were thickened and even ruptured, (3) mesophyll cells and chloroplasts were gradually damaged to a complete disorganization containing more starch, (4) leaf Na and Cl contents increased while leaf K content decreased, (5) leaf proline content and the activities of catalase (CAT) and superoxide dismutase (SOD) increased significantly, and (6) leaf malondialdehyde (MDA) content increased significantly and stomatal area and chlorophyll content decline were also detected. Severe salt stress (200 mM NaCl) inhibited plantlet growth. These results indicated that potato plantlets adapt to salt stress to some extent through accumulating osmoprotectants, such as proline, increasing the activities of antioxidant enzymes, such as CAT and SOD. The outcomes of this study provide ultrastructural and physiological insights into characterizing potential damages induced by salt stress for selecting salt-tolerant potato cultivars.

Evidence for microbial degradation of polyvinyl chloride (PVC) has previously been reported, but little is known about the degrading strains and enzymes. Here, we isolate a PVC-degrading bacterium from the gut of insect larvae and shed light on the PVC degradation pathway using a multi-omic approach. We show that the larvae of an insect pest, Spodoptera frugiperda, can survive by feeding on PVC film, and this is associated with enrichment of Enterococcus, Klebsiella and other bacteria in the larva’s gut microbiota. A bacterial strain isolated from the larval intestine (Klebsiella sp. EMBL-1) is able to depolymerize and utilize PVC as sole energy source. We use genomic, transcriptomic, proteomic, and metabolomic analyses to identify genes and proteins potentially involved in PVC degradation (e.g., catalase-peroxidase, dehalogenases, enolase, aldehyde dehydrogenase and oxygenase), and propose a PVC biodegradation pathway. Furthermore, enzymatic assays using the purified catalase-peroxidase support a role in PVC depolymerization.

The room-temperature ferromagnetism of Zn1−x Al x O nanoparticles synthesized by a sol−gel method is reported in this paper. X-ray diffraction and selected area electron diffraction results show that the Al atoms have successfully substituted for some of the Zn atoms in the ZnO lattice without forming other new phases. The results also show that the samples possess a typical wurtzite structure. Declaration of ferromagnetism at room temperature has been established with the observed hysteresis and the coercive field in hysteresis loops. Magnetic measurements indicate that the saturation magnetization of the samples is sensitive to the content of Al dopants and that, for Zn0.97Al0.03O, the saturation magnetization reaches the maximum of 0.012 emu/g. Combining with the results of Raman, photoluminescence, and X-ray photoelectron spectroscopies, it is suggested that the observed ferromagnetic ordering of the Zn1−x Al x O nanoparticles is related to the doping-induced oxygen vacancies.

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