ABSTRACT
The novel 2019 Corona viruses are enveloped RNA genome virus, with a 79% genome similarity to the previous 2003 SARS Coronavirus-1 (SARS-CoV-1). Up to date the confirmed cases worldwide 11,327,790 And 209,509 in Saudi Arabia. The SARS-CoV-2 is a single strand RNA belongs to Beta corona virus. The phylogenetic analysis suspected that bats are the primary reservoir, however the zoonotic intermediate host that transfer SARS-CoV-2 to human is not identified. The glycoprotein spike exclusively on the SARS-CoVs-2 species binds to the host cell receptor through a region called receptor-binding domain (RBD) and mediates viral entry. SARS-CoV-2 targeting Angiotensin-converting enzyme 2 explain the reason behind the infection of the respiratory system especially. S glycoprotein is the most important protein of the virus while it is the best target for entry inhibitors, neutralizing antibody, and vaccine development. Besides the role of antibodies to eliminate virus separation, it can also reas viral entry in some virus species through a mechanism termed antibody-dependent enhancement (ADE) under certain conditions. This mechanism is the main block in the way of vaccine development against SARS-CoV 2. The balance between getting the induction of immunity protection and developing an enhanced susceptibility to virus infection after vaccination against SARS-CoV-2 is a highly sensitive and delicate approach and has a high risk. This novel version of the virus has many routes for infection, this may describe its ability to spread at a high rate and its high aggressivity compared to the previous one every year.
ABSTRACT
Citrinin is a nephrotoxic mycotoxin produced by several species of the genus Aspergillus, Penicillium and Monascus. Citrinin is generally formed after harvest and occurs mainly in stored grains The efficacy of different concentrations of aqueous leaf extracts of Aervalanata, Nerium oleander Rhazya stricta Decne and Cleome amblyocarpa (5 to 10 mg/mL) on growth and citrinin production in two fungal strains Penicillium notatum and Aspergillus niger was investigated. Mycotoxin production and fungal biomass by the isolates was suppressed, depending on the concentration of the plant extract added to culture media at the time of spore inoculation. Citrinin production in fungal mycelia grown for 15 days in culture media containing 5-10 mg/mL of the aqueous extracts of A. lanata, N. oleander, R. stricta Decne and C. amblyocarpa showed inhibition of approximately 14.2 to 91.8 % in Penicillium notatum and 13.4 to 90.3% in Aspergillus niger. Among the all four extracts Rhazya stricta Decne was more efficient than other tested plant extracts in inhibiting the citrinin production ranging from 22.4 to 91.8% in P. notatum and 32.6 to 93.2% in A. niger.