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The flotation separation of chalcopyrite from pyrite has attracted increasing attention due to the consumption of vast water resources and depressants. This study proposed the seawater oxidation pretreatment for non-depressant flotation separation of chalcopyrite from pyrite, as an effective and environmentally friendly strategy. Without the addition of depressants, seawater oxidation for 3 d effectively depressed pyrite flotation, with the highest recovery difference greater than 70% and a selectivity index greater than 6 between chalcopyrite and pyrite. The surface investigation showed that pyrite surface was more readily oxidized to form hydrophilic Fe oxidants/oxyhydroxides, as compared to that of chalcopyrite. Further UV-visible spectrophotometer and Fourier transform infrared spectrum (FTIR) results indicated that xanthate was less adsorbed onto the treated pyrite surface, resulting in un-floatable particles. Chalcopyrite surface was changed slightly due to seawater oxidation, thereby insignificantly affecting its flotation. The coordination theory was further used to reveal the combination mechanisms between xanthate and pyrite or chalcopyrite. This study therefore provides a promising strategy to effectively separate chalcopyrite from pyrite, especially in the freshwater-deficient area.

Abstract Introduction The transmission pathways of coronavirus disease 2019 (COVID‐19) remain not completely clear. In this case study the test for the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) in pharyngeal swab and anal swab were compared. Case presentation A 3‐month‐old girl was admitted to our hospital with COVID‐19. Her parents had both been diagnosed with COVID‐19. The results of pharyngeal swab and anal swab of the little girl were recorded and compared during the course of the disease. The oropharyngeal specimen showed negative result for SARS‐CoV‐2 on the 14th day after onset of the illness. However, the anal swab was still positive for SARS‐CoV‐2 on the 28th day after the onset of the illness. Conclusion The possibility of fecal‐oral transmission of COVID‐19 should be assessed. Personal hygiene during home quarantine merits considerable attention.

Mycorrhizal inoculation stimulates growth, photosynthesis and nutrient uptake in a wide range of host plants. However, the ultimate effects of arbuscular mycorrhyzal (AM) symbiosis vary with the plants and fungal species involved in the association. Therefore, identification of the appropriate combinations of AM fungi (AMF) that interact synergistically to improve their benefits is of high significance. Here, three AM fungal compositions namely VT (Claroideoglomus sp., Funneliformis sp., Diversispora sp., Glomus sp., and Rhizophagus sp.) and BF (Glomus intraradices, G. microageregatum BEG and G. Claroideum BEG 210), and Funneliformis mosseae (Fm) were investigated with respect to the growth, gas exchange parameters, enzymes activities in Calvin cycles and related gene expression in cucumber seedlings. The results showed that VT, BF and Fm could successfully colonize cucumber root to a different degree with the colonization rates 82.38, 74.65, and 70.32% at 46 days post inoculation, respectively. The plant height, stem diameter, dry weight, root to shoot ratio of cucumber seedlings inoculated with AMF increased significantly compared with the non-inoculated control. Moreover, AMF colonization greatly increased the root activity, chlorophyll content, net photosynthetic rate, light saturated rate of the CO2 assimilation (Asat), maximum carboxylation rate (Vcmax) and maximum ribulose-1,5-bis-phosphate (RuBP) regeneration rate (Jmax), which were increased by 52.81, 30.75, 58.76, 47.00, 69.15, and 65.53% when inoculated with VT, respectively. The activities of some key enzymes such RuBP carboxylase/oxygenase (RuBisCO), D-fructose-1,6-bisphosphatase (FBPase), D-fructose-6-phosphatase (F6P) and ribulose-5-phosphate kinase (Ru5PK), and related gene expression involved in the Calvin cycle including RCA, FBPase, FBPA, SBPase, rbcS and rbcL were upregulated by AMF colonization. AMF inoculation also improved macro- and micro nutrient contents such as N, P, K, S, Ca, Cu, Fe, Mn, Mg, and Zn in roots. Further analysis revealed that inoculation with VT had relatively better effect on growth of cucumber seedling followed by BF and Fm, indicating that AMF composition consisting of distant AMF species may have a better effect than a single or closely related AMF spp. This study advances the understanding of plant responses to different AM fungi toward development of strategies on AMF-promoted vegetable production.

Ubiquitination is a common regulatory mechanism, playing a critical role in diverse cellular and developmental processes in eukaryotes. However, a few reports on the functional correlation between E3 ubiquitin ligases and reactive oxygen species (ROS) or reactive nitrogen species (RNS) metabolism in response to stress are currently available in plants. In the present study, the E3 ubiquitin ligase gene AdBiL (Adi3 Binding E3 Ligase) was introduced into tomato line Ailsa Craig via Agrobacterium-mediated method. Transgenic lines were confirmed for integration into the tomato genome using PCR. Transcription of AdBiL in various transgenic lines was determined using real-time PCR. Evaluation of stress tolerance showed that T1 generation of transgenic tomato lines showed only mild symptoms of chilling injury as evident by higher biomass accumulation and chlorophyll content than those of non-transformed plants. Compared with wild-type plants, the contents of AsA, AsA/DHA, GSH and the activity of GaILDH, γ-GCS and GSNOR were increased, while H2O2, O2.−, MDA, NO, SNOs, and GSNO accumulations were significantly decreased in AdBiL overexpressing plants in response to chilling stress. Furthermore, transgenic tomato plants overexpressing AdBiL showed higher activities of enzymes such as G6PDH, 6PGDH, NADP-ICDH, and NADP-ME involved in pentose phosphate pathway (PPP). The transgenic tomato plants also exhibited an enhanced tolerance against the necrotrophic fungus Cladosporium fulvum. Tyrosine nitration protein was activated in the plants infected with leaf mold disease, while the inhibition could be recovered in AdBiL gene overexpressing lines. Taken together, our results revealed a possible physiological role of AdBiL in the activation of the key enzymes of AsA–GSH cycle, PPP and down-regulation of GSNO reductase, thereby reducing oxidative and nitrosative stress in plants. This study demonstrates an optimized transgenic strategy using AdBiL gene for crop improvement against biotic and abiotic stress factors.