Research Articles (Microbial, Biochemical and Food Biotechnology)
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Browsing Research Articles (Microbial, Biochemical and Food Biotechnology) by Author "Folorunso, Olufemi S."
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Item Open Access Cryptococcal protease(s) and the activation of SARS-CoV-2 spike (S) protein(MDPI, 2022) Mjokane, Nozethu; Maliehe, Maphori; Folorunso, Olufemi S.; Ogundeji, Adepemi O.; Gcilitshana, Onele M. N.; Albertyn, Jacobus; Pohl, Carolina H.; Sebolai, Olihile M.In this contribution, we report on the possibility that cryptococcal protease(s) could activate the SARS-CoV-2 spike (S) protein. The S protein is documented to have a unique four-amino-acid sequence (underlined, SPRRAR|S) at the interface between the S1 and S2 sites, that serves as a cleavage site for the human protease, furin. We compared the biochemical efficiency of cryptococcal protease(s) and furin to mediate the proteolytic cleavage of the S1/S2 site in a fluorogenic peptide. We show that cryptococcal protease(s) processes this site in a manner comparable to the efficiency of furin (p > 0.581). We conclude the paper by discussing the impact of these findings in the context of a SARS-CoV-2 disease manifesting while there is an underlying cryptococcal infection.Item Open Access The possible role of microbial proteases in facilitating SARS-CoV-2 brain invasion(MDPI, 2021) Mjokane, Nozethu; Folorunso, Olufemi S.; Ogundeji, Adepemi O.; Sebolai, Olihile M.SARS-CoV-2 has been shown to display proclivity towards organs bearing angiotensinconverting enzyme (ACE2) expression cells. Of interest herein is the ability of the virus to exhibit neurotropism. However, there is limited information on how this virus invades the brain. With this contribution, we explore how, in the context of a microbial co-infection using a cryptococcal co-infection as a model, SARS-CoV-2 could reach the brain. We theorise that the secretion of proteases by disseminated fungal cells might also activate the S2 domain of the viral spike glycoprotein for membrane fusion with brain endothelial cells leading to endocytosis. Understanding this potential invasion mechanism could lead to better SARS-CoV-2 intervention measures, which may also be applicable in instances of co-infection, especially with protease-secreting pathogens.Item Open Access The repurposing of acetylsalicylic acid as a photosensitiser to inactivate the growth of cryptococcal cells(MDPI, 2021) Ogundeji, Adepemi O.; Mjokane, Nozethu; Folorunso, Olufemi S.; Pohl, Carolina H.; Nyaga, Martin M.; Sebolai, Olihile M.Photodynamic treatment (PDT) is often successful when used against aerobic microbes, given their natural susceptibility to oxidative damage. To this end, the current study aimed to explore the photodynamic action of acetylsalicylic acid (ASA; aspirin, which is commonly used to treat non-infectious ailments), when administered to respiring cryptococcal cells. The treatment of cryptococcal cells, i.e., exposure to 0.5 or 1 mM of ASA in the presence of ultraviolet light (UVL) for 10 min, resulted in a significant (p < 0.05) reduction in the growth of tested cells when compared to non-treated (non-Rx) cells, i.e., no ASA and no UVL. The treated cells were also characterised by diseased mitochondria, which is crucial for the survival of respiring cells, as observed by a significant (p < 0.05) loss of mitochondrial membrane potential (DYM) and significant (p < 0.05) accumulation of reactive oxygen species (ROS) when compared to non-Rx cells. Moreover, the photolytic products of acetylsalicylic acid altered the ultrastructural appearance of treated cells as well as limited the expression levels of the capsular-associated gene, CAP64, when compared to non-Rx cells. The results of the study highlight the potential use of ASA as a photosensitiser that is effective for controlling the growth of cryptococcal cells. Potentially, this treatment can also be used as an adjuvant, to complement and support the usage of current anti-microbial agents.