Oxidative stress triggers a lethal cascade, leading to Parkinson’s disease by causing degeneration of dopaminergic neurons. In this study, eight antioxidants were screened for their neuroprotective effect on PC12 cells (pheochromocytoma cell line) under oxidative stress induced by salsolinol (OSibS). Hydroxytyrosol was found to be the strongest neuroprotective agent; it improved viability of PC12 cells by up to 81.69% under OSibS. Afterward, two synaptic vesicle proteins, synapsin-1 and septin-5, were screened for their neuroprotective role; the overexpression of synapsin-1 and the downregulation of septin-5 separately improved the viability of PC12 cells by up to 71.17% and 67.00%, respectively, compared to PC12 cells only treated with salsolinol (PoTwS) under OSibS. Subsequently, the PC12+syn⁺+sep⁻ cell line was constructed and pretreated with 100 µM hydroxytyrosol, which improved its cell viability by up to 99.03% and led to 14.71- and 6.37-fold reductions in the levels of MDA and H₂O₂, respectively, and 6.8-, 12.97-, 10.57-, and 7.57-fold increases in the activity of catalase, glutathione reductase, superoxide dismutase, and glutathione peroxidase, respectively, compared to PoTwS under OSibS. Finally, alcohol dehydrogenase-6 from Saccharomyces cerevisiae was expressed in PC12+syn⁺+sep⁻ cells to convert 3,4-dihydroxyphenylacetaldehyde (an endogenous neurotoxin) into hydroxytyrosol. The PC12+syn⁺+sep⁻+ADH6⁺ cell line also led to 22.38- and 12.33-fold decreases in the production of MDA and H₂O₂, respectively, and 7.15-, 13.93-, 12.08-, and 8.11-fold improvements in the activity of catalase, glutathione reductase, superoxide dismutase, and glutathione peroxidase, respectively, compared to PoTwS under OSibS. Herein, we report the endogenous production of a powerful antioxidant, hydroxytyrosol, from 3,4-dihydroxyphenylacetaldehyde, and evaluate its synergistic neuroprotective effect, along with synapsin-1 and septin-5, on PC12 cells under OSibS.

We have previously reported that squalene overproducing yeast self-downregulate the expression of the ethanol pathway (non-essential pathway) to divert the metabolic flux to the squalene pathway. In this study, the effect of co-production of squalene and ethanol on other non-essential pathways (fusel alcohol pathway, FA) of Saccharomyces cerevisiae was evaluated. However, before that, 13 constitutive promoters, like IRA1p, PET9p, RHO1p, CMD1p, ATP16p, USA3p, RER2p, COQ1p, RIM1p, GRS1p, MAK5p, and BRN1p, were engineered using transcription factor bindings sites from strong promoters HHF2p (−300 to −669 bp) and TEF1p (−300 to −579 bp), and employed to co-overexpress squalene and ethanol pathways in S. cerevisiae. The FSE strain overexpressing the key genes of the squalene pathway accumulated 56.20 mg/L squalene, a 16.43-fold higher than wild type strain (WS). The biogenesis of lipid droplets was stimulated by overexpressing DGA1 and produced 106 mg/L squalene in the FSE strain. AFT1p and CTR1p repressible promoters were also characterized and employed to downregulate the expression of ERG1, which also enhanced the production of squalene in FSE strain up to 42.85- (148.67 mg/L) and 73.49-fold (255.11 mg/L) respectively. The FSE strain was further engineered by overexpressing the key genes of the ethanol pathway and produced 40.2 mg/mL ethanol in the FSE1 strain, 3.23-fold higher than the WS strain. The FSE1 strain also self-downregulated the expression of the FA pathway up to 73.9%, perhaps by downregulating the expression of GCN4 by 2.24-fold. We demonstrate the successful tuning of the strength of yeast promoters and highest coproduction of squalene and ethanol in yeast, and present GCN4 as a novel metabolic regulator that can be manipulated to divert the metabolic flux from the non-essential pathway to engineered pathways.

Nanotechnology offers exciting prospects against infectious agents, particularly multidrug resistance bacteria (MDR), which is the roaring concern of this era. Zinc oxide nanoparticles (ZnO-Nps) efficiently deliver therapeutic agents into living systems due to their biocompatibility and bioactivity, which make them highly effective against infectious pathogens. The present investigation was designed to investigate the impact of the ZnO-Nps in combination with the Piperacillin-Tazobactam (TZP) drug against MDR. TZP are beta-lactam antibiotics highly effective against Gram-positive and Gram-negative bacteria such as Pseudomonas aeruginosa, and are recommended for the empirical treatment of Febrile neutropenia (FN) associated with chemotherapy treatment. For this study, three different-sized ZnONp combinations were used. The extended-spectrum beta-lactamase (ESBLs) producing Escheria coli and MDR P. aeruginosa strain sensitivity profiling towards different combinations of ZnO-Nps and Piperacillin-Tazobactam were measured. The synthesized Zno-Nps w ere d esignated a s Z n-1, Z n- 2, and Zn-3 based on their sizes, and were made in different combinations with the commercially available drug TZP (ZnO-Nps+ Drug) against MDR E.coli and P. aeruginosa. There was no synergistic effect observed against growth inhibition of E.coli. The combined dose of Zn-1 and TZP showed better antibacterial efficacy even as compared to the pure drug against P. aeruginosa. The study revealed that the dosage and biological activity of drugs used to treat fatal human diseases like cancer can be decreased while their efficacy can be boosted by using ZnO nanoparticles as powerful drug delivery systems.