First report on disinfection performance for SARS-CoV-2 in medical wastewater • Incomplete removal of SARS-CoV-2 RNA under WHO guideline • High level of DBPs when SARS-CoV-2 is completed removed.

The outbreak of coronavirus infectious disease-2019 (COVID-19) pneumonia raises the concerns of effective deactivation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in medical wastewater by disinfectants. In this study, we evaluated the presence of SARS-CoV-2 viral RNA in septic tanks of Wuchang Fangcang Hospital and found the high level of (0.05-1.87)×10 4 copies/L after disinfection with sodium hypochlorite. Embedded viruses in stool particles might be released in septic tanks, behaving as a source of SARS-CoV-2 and potentially contributing to its spread through drainage pipelines. Current recommended disinfection strategy (free chlorine above 6.5 mg/L after 1.5-hour contact) needs to be reevaluated to completely remove SARS-CoV-2 viral RNA in non-centralized disinfection system and effectively deactivate SARS-CoV-2. The effluents showed negative results for SARS-CoV-2 viral RNA when overdosed with sodium hypochlorite but had high a level of disinfection by-product residuals, possessing significant ecological risks.

The major concern regarding the biocide triclosan (TCS) stems from its potential coselection for antibiotic resistance. However, environmental impacts are often investigated using high concentrations and acute exposure, while predicted releases are typified by chronic low concentrations. Moreover, little information is available regarding the reversibility of TCS and derived antibiotic resistance with diminishing TCS usage. Here, the model Gramnegative bacterium Escherichia coli was exposed to 0.01 mg/L TCS continuously for more than 100 generations. The adapted cells gained considerable resistance to TCS as indicated by a significant increase in the minimal inhibitory concentration (MIC 50 ) from 0.034 to 0.581 mg/L. This adaptive evolution was attributed to overexpression and mutation of target genes (i.e., fabI) as evidenced by transcriptomic and genomic analyses. However, only mild tolerance to various antibiotics was observed, possibly due to reduced membrane permeability and biofilm formation. After TCS exposure ceased, the adapted cells showed persistent resistance to TCS due to inheritable genetic mutations, whereas their antibiotic tolerance declined over time. Our results suggest that extensive use of TCS may promote the evolution and persistence of TCS-resistant bacterial pathogens. A quantitative definition of the conditions under which TCS selects for multidrug resistance in the environment is crucially needed.

Sulfidation of silver nanoparticles may camouflage its long term effect with imperceptible acute toxicity.

Catharanthus roseus (L.) G. Don is a plant belonging to the genus Catharanthus of the Apocynaceae family. It contains more than one hundred alkaloids, of which some exhibit significant pharmacological activities. Chitooligosaccharides are the only basic aminooligosaccharides with positively charged cations in nature, which can regulate plant growth and antioxidant properties. In this study, the leaves of Catharanthus roseus were sprayed with chitooligosaccharides of different molecular weights (1 kDa, 2 kDa, 3 kDa) and different concentrations (0.01 μg/mL, 0.1 μg/mL, 1 μg/mL and 10 μg/mL). The fresh weights of its root, stem and leaf were all improved after chitooligosaccharides treatments. More importantly, the chitooligosaccharides elicitor strongly stimulated the accumulation of vindoline and catharanthine in the leaves, especially with the treatment of 0.1 μg/mL 3 kDa chitooligosaccharides, the contents of them were increased by 60.68% and 141.54%, respectively. Furthermore, as the defensive responses, antioxidant enzymes activities (catalase, glutathione reductase, ascorbate peroxidase, peroxidase and superoxide dismutase) were enhanced under chitooligosaccharides treatments. To further elucidate the underlying mechanism, qRT-PCR was used to investigate the genes expression levels of secologanin synthase (SLS), strictosidine synthase (STR), strictosidine glucosidase (SGD), tabersonine 16-hydroxylase (T16H), desacetoxyvindoline-4-hydroxylase (D4H), deacetylvindoline-4-O-acetyltransferase (DAT), peroxidase 1 (PRX1) and octadecanoid-responsive Catharanthus AP2-domain protein 3 (ORCA3). All the genes were significantly up-regulated after chitooligosaccharides treatments, and the transcription abundance of ORCA3, SLS, STR, DAT and PRX1 reached a maximal level with 0.1 μg/mL 3 kDa chitooligosaccharides treatment. All these results suggest that spraying Catharanthus roseus leaves with chitooligosaccharides, especially 0.1 μg/mL of 3 kDa chitooligosaccharides, may effectively improve the pharmaceutical value of Catharanthus roseus.