Possible correlation between the probiotic activity of bacterial honey isolates and the in vitro inhibition of coronavirus 2 replication responsible for acute respiratory syndromes

Various strategies, like those using vaccines and antibiotics, have been examined for the prevention and treatment of virus's diseases, but until this moment infection control is not at sufficient level. Exopolysaccharides, especially from probiotics, became one of the most innovative approaches for antiviral agents. This research tried to highlight the effect of a probiotic polysaccharide, such as levan, in COVID-19 prevention. Accordingly, 5 levans types previously obtained from bacterial honey isolates were tested against COVID-19. The most promising result was recorded with levans from Pseudomonas aeruginosa HI1 (levAE) and Bacillus subtilis 9A (lev9A). The lowest cytotoxicity was obtained from lev9A (CC50=5.567e+006 mg/ml) and the most promising IC50 was obtained by levAE (10.75 mg/ml) followed by lev13M (142.5 mg/ml) then lev9A (1299 mg/ml). The dialysis process of levAE greatly affected the virus inhibition activity (IC50 of levAE/D =7.773e+006 mg/ml). Pseudomonas aeruginosa HI1 and Bacillus subtilis 9A were highly tolerant to the acidic (pHs 2, 3) and alkaline conditions (pHs 9, 11). Moreover, when incubated with 0.3 bile salt for 24h, their surviving rates recorded 94% and 100% respectively. H2O2 tolerance showed 77% surviving of Pseudomonas aeruginosa HI1 and 100% surviving of Bacillus subtilis 9A. The blood hemolysis and the antibiotics sensitivity tests confirmed the isolate's safety. The hypothesis that the isolates adhere to the lung cells, could explain the ability of the isolates and their levans to inhibit covid-19 replication. © 2022 National Information and Documentation Center.

The Impact of COVID-19 on the Malaysian Stock Market: Evidence from an Autoregressive Distributed Lag Bound Testing Approach

This paper investigates the impact of the domestic and global outbreak of the coronavirus (COVID-19) pandemic on the trading size of the Malaysian stock (MS) market The theoretical model posits that stock markets arc affected by their response to disasters and events that arise in the international or local environments, as well as to several financial factors such as stock volatility and spread bid-ask prices. Using daily time-series data from 27 January to 12 May 2020, this paper utilizes the traditional Augmented Dickey and Fuller (ADF) technique and Zivot and Andrews with structural break' procedures for a stationarity test analysis, while the autoregressive distributed lag (ARDL) method is applied according to the trading size of the MS market model. The analysis considered ahnost all 789 listed companies investing in the main stock market of Malaysia. The results confirmed our hypotheses that both the daily growth in the active domestic and global cases of coronavirus (COVID-19) has significant negative effects on the daily trading size of the stock market in Malaysia. Although the COVID-19 has a negative effect on the Malaysian stock market, the findings of this study suggest that the COVID-19 pandemic may have an asymmetric effect on the market.