Tracking SARS-CoV-2 in rivers as a tool for epidemiological surveillance.

The aim of this work was to evaluate if rivers could be used for SARS-CoV-2 surveillance. Five sampling points from three rivers (AR-1 and AR-2 in Arenales River, MR-1 and MR-2 in Mojotoro River, and CR in La Caldera River) from Salta (Argentina), two of them receiving discharges from wastewater plants (WWTP), were monitored from July to December 2020. Fifteen water samples from each point (75 in total) were collected and characterized physico-chemically and microbiologically and SARS-CoV-2 was quantified by RT-qPCR. Also, two targets linked to human contributions, human polyomavirus (HPyV) and RNase P, were quantified and used to normalize SARS-CoV-2 concentration, which was compared to reported COVID-19 cases. Statistical analyses allowed us to verify the correlation between SARS-CoV-2 and the concentration of fecal indicator bacteria (FIB), as well as to find similarities and differences between sampling points. La Caldera River showed the best water quality; FIBs were within acceptable limits for recreational activities. Mojotoro River's water quality was not affected by the northern WWTP of the city. Instead, Arenales River presented the poorest water quality; at AR-2 was negatively affected by the discharges of the southern WWTP, which contributed to significant increase of fecal contamination. SARS-CoV-2 was found in about half of samples in low concentrations in La Caldera and Mojotoro Rivers, while it was high and persistent in Arenales River. No human tracers were detected in CR, only HPyV was found in MR-1, MR-2 and AR-1, and both were quantified in AR-2. The experimental and normalized viral concentrations strongly correlated with reported COVID-19 cases; thus, Arenales River at AR-2 reflected the epidemiological situation of the city. This is the first study showing the dynamic of SARS-CoV-2 concentration in an urban river highly impacted by wastewater and proved that can be used for SARS-CoV-2 surveillance to support health authorities.

Biological activity and chemical characterization of Pouteria lucuma seeds: A possible use of an agricultural waste.

Pouteria lucuma fruit is widely used to prepare cakes, ice creams and juice or also commercialized as pulp and flour. As result of this business thousands of tons of seeds are generated as an agricultural waste. This study presents the antioxidant and antiulcer activities, and the identification of secondary metabolites by UHPLC/ESI/MS/MS of an agroindustrial waste of Pouteria lucuma seeds. Fifty-nine compounds were tentatively identified including eight aminoacids, five organic acids, one nucleoside, five phenolic acids, five phenolic alcohols, nineteen flavonoids, six lipids, and seven unknowns in the methanol extract of P. lucuma seeds. The total phenolic content of the seeds was 52.82 ±â€¯0.09 µmol GAE/g dry weight, while total flavonoid content was 5.99 ±â€¯0.01 µmol Q/g dry weight. The antioxidant activity was 58.14 ±â€¯0.05, 66.97 ±â€¯0.00, 272.50 ±â€¯0.00, and 67.02 ±â€¯2.23 for the DPPH, ABTS, FRAP, and superoxide anion assays, respectively. The highest gastroprotective activity was obtained at 100 mg/kg (78%), which as higher than the positive control lansoprazole (75%). Our findings showed that P. lucuma seed extracts have moderate to high antioxidant activity and gastroprotective properties. Therefore, it was demostrated that lucuma seeds commonly eliminated as an agricultural industry waste, could be useful for the preparation of nutritional supplements.