p53 Transactivation and the Impact of Mutations, Cofactors and Small Molecules Using a Simplified Yeast-Based Screening System

The p53 tumor suppressor, which is altered in most cancers, is a sequence-specific transcription factor that is able to modulate the expression of many target genes and influence a variety of cellular pathways. Inactivation of the p53 pathway in cancer frequently occurs through the expression of mutant p53 protein. In tumors that retain wild type p53, the pathway can be altered by upstream modulators, particularly the p53 negative regulators MDM2 and MDM4. promoter, ii) single copy, chromosomally located p53-responsive and control luminescence reporters, iii) enhanced chemical uptake using modified ABC-transporters, iv) small-volume formats for treatment and dual-luciferase assays, and v) opportunities to co-express p53 with other cofactor proteins. This robust system can distinguish different levels of expression of WT and mutant p53 as well as interactions with MDM2 or 53BP1.We found that the small molecules Nutlin and RITA could both relieve the MDM2-dependent inhibition of WT p53 transactivation function, while only RITA could impact p53/53BP1 functional interactions. PRIMA-1 was ineffective in modifying the transactivation capacity of WT p53 and missense p53 mutations. This dual-luciferase assay can, therefore, provide a high-throughput assessment tool for investigating a matrix of factors that can influence the p53 network, including the effectiveness of newly developed small molecules, on WT and tumor-associated p53 mutants as well as interacting proteins

Efficacy of Citrus sinensis essential oils in the control of Pseudomonas syringae pv. tomato and Fusarium oxysporum f.sp. radicis lycopersici

Essential oils represent a promising option for pathogen control due to their natural antimicrobial properties. This study evaluated the antibacterial and antifungal activity, against phytopathogenic species, of two varieties of essential oils extracted from Citrus sinensis peel: C. sinensis “Navel Orange” and C. sinensis “Tarocco”. As regards antibacterial activity, after determining the minimum inhibitory concentration, equal to 5% (w/w), against Pseudomonas syringae pv. tomato, the causative agent of bacterial spot on tomatoes, curative efficacy tests were conducted. The inoculated plastic surfaces were treated with essential oils and subsequently analyzed to verify the presence of the pathogen by plating on selective media and specific polymerase chain reaction. The antifungal activity of the same essential oils was studied against Fusarium oxysporum f.sp. radicis lycopersici, the agent responsible for root rot in tomatoes. Tomato seeds were exposed during germination to different concentrations of suspended essential oils. After a few days, blackening of the roots, if present, was observed as an indicator of disease. The results highlighted the significant effectiveness of essential oils in both assays, suggesting their potential use as sustainable tools for the management of fungal infections in agriculture and for the disinfection of surfaces promoting the reuse of agricultural artifacts with a view to circular economy

Potential of Salvia extracts as natural insecticides against the tomato leaf miner, Tuta absoluta

The tomato leaf miner, Tuta absoluta, is a major threat to solanaceous crops, particularly tomatoes, and can cause yield losses of up to 100%. The rapid spread of the pest and increasing resistance to conventional insecticides highlight the need for alternative control methods [1,2]. Considering these challenges, we evaluated the insecticidal and antifeedant activities of dichloromethane surface ex- tracts from four Salvia species (S. buchanani, S. corrugata, S. discolor, and S. namaensis) against T. absoluta larvae using a leaf-dip bioassay protocol (IRAC susceptibility test method) with few modifi- cations. LC-MS analysis revealed that the extracts were rich in abietane-type diterpenes and highly methoxylated flavonoids, which are known for their bioactive properties. Preliminary screening at a concentration of 2.5 mg/mL revealed S. discolor to be the most effective, demonstrating statistically higher larval mortality than the commercial insecticide Spinosad. Encouraged by these findings, we further evaluated the effects of the species at varying concentrations (0.16, 0.31, 0.62, 1.25, and 5.0 mg/mL). S. discolor demonstrated remarkable potency, with an LC50 of 0.013 mg/mL. Additionally S. discolor consistently induced strong feeding inhibition across all tested concentrations, suggesting its potential as a possible natural alternative to synthetic insecticides. Future studies will be carried out to investigate the compounds responsible for these effects

Exploring the phytochemical profile and antimicrobial activity of Salvia discolor against phytopathogens

In the present study, we carried out phytochemical characterisation and antimicrobial activity of dichloromethane extract from aerial parts of Salvia discolor Kunth (Lamiaceae). This research aimed to fill the gap in understanding the potential applications of this underexplored species. The dichloromethane extract obtained from the plant surface of S. discolor after repeated chromatographic separation yielded a novel compound with clerodane diterpene skeleton and various known compounds, 8,3’-dihydroxy-6,7,4’-trimethoxyflavone[1], 5,7-dihydroxy-3,4’-dimethoxyflavone[2], divinatorin A[3] and patagonic acid[4], which were identified through spectroscopic NMR analysis, including DEPT, TOCSY, HSQC, HMBC, and ROESY experiments. Furthermore, we assessed the antimicrobial potential of the ground extract against three strains of phytopathogenic bacteria (Clavibacter michiganesis subsp. michiganesis, Pectobacterium carotovorum subsp. carotovorum, Pseudomonas syringae pv. tomato) and nine strains of phytopathogenic fungi (Alternaria solani, Botrytis cinerea, Colletotrichum lindemuthianum, Fusarium solani, Fusarium oxysporum fsp. lactucae race 1, Phoma betae, Phaemoniella chlamydospora, Pythium dissocotum, Stemphylium sp.), selected among the more common pathogens of agricultural interest. Our results showed that the extract was only effective at concentrations above 1000 μg/mL, showing a low antibacterial activity. Conversely, the extract showed a significant antifungal activity against all the fungi tested at different concentrations (100, 250, 500, 750 and 1000 μg/mL). The extract inhibited more than 80% of mycelial growth of F. solani, P. chlamydospora and P. dissotocum, and showed more than 50% inhibition against A. solani, B. cinerea, P. betae and Stemphylium sp. On the other hand, there was minimal inhibition (<30%) against C. lindemuthianum and F. oxysporum fsp. lactucae race 1