The bacterial translational apparatus is an ideal target for the search of new antibiotics. In fact, it performs an essential process carried out by a large number of potential subtargets for antibiotic action. Moreover, it is sufficiently different in several molecular details from the apparatus of Eukarya and Archaea to generally ensure specificity for the bacterial domain. This applies in particular to translation initiation, which is the most different step in the process. In bacteria, the 30S ribosomal subunit directly binds to the translation initiation region, a site within the messenger RNA (mRNA) 5′-untranslated region (5′-UTR). 30S binding is mediated by the interaction of both the 16S ribosomal RNA and the ribosomal protein S1 with specific regions of the mRNA 5′-UTR. An alternative, S1-independent pathway is enjoyed by leaderless mRNAs (i.e., transcripts devoid of a 5′-UTR). We have developed a simple fluorescence-based whole-cell assay in Escherichia coli to find inhibitors of the canonical S1-dependent translation initiation pathway. The assay has been set up both in a common E. coli laboratory strain and in a strain with an outer membrane permeability defect. Compared with other whole-cell assays for antibacterials, the major advantages of the screen described here are high sensitivity and specificity.

Assessing the toxic effect in living organisms remains a major issue for the development of safe nanomedicines and exposure of researchers involved in the synthesis, handling and manipulation of nanoparticles. In this study, we demonstrate that Caenorhabditis elegans could represent an in vivo model alternative to superior mammalians for the collection of several physiological functionality parameters associated to both short-term and long-term effects of colloidally stable nanoparticles even in absence of microbial feeding, usually reported to be necessary to ensure appropriate intake. Contextually, we investigated the impact of surface charge on toxicity of superparamagnetic iron oxide coated with a wrapping polymeric envelop that confers them optimal colloidal stability. By finely tuning the functional group composition of this shallow polymer–obtaining totally anionic, partially pegylated, partially anionic and partially cationic, respectively–we showed that the ideal surface charge organization to optimize safety of colloidal nanoparticles is the one containing both cationic and anionic groups. Our results are in accordance with previous evidence that zwitterionic nanoparticles allow long circulation, favorable distribution in the tumor area and optimal tumor penetration and thus support the hypothesis that zwitterionic iron oxide nanoparticles could be an excellent solution for diagnostic imaging and therapeutic applications in nanooncology.

Amyloid aggregation of human ataxin-3 (ATX3) is responsible for spinocerebellar ataxia type 3, which belongs to the class of polyglutamine neurodegenerative disorders. It is widely accepted that the formation of toxic oligomeric species is primarily involved in the onset of the disease. For this reason, to understand the mechanisms underlying toxicity, we expressed both a physiological (ATX3-Q24) and a pathological ATX3 variant (ATX3-Q55) in a simplified cellular model, Escherichia coli. It has been observed that ATX3-Q55 expression induces a higher reduction of the cell growth compared to ATX3-Q24, due to the bacteriostatic effect of the toxic oligomeric species. Furthermore, the Fourier transform infrared microspectroscopy investigation, supported by multivariate analysis, made it possible to monitor protein aggregation and the induced cell perturbations in intact cells. In particular, it has been found that the toxic oligomeric species associated with the expression of ATX3-Q55 are responsible for the main spectral changes, ascribable mainly to the cell envelope modifications. A structural alteration of the membrane detected through electron microscopy analysis in the strain expressing the pathological form supports the spectroscopic results.

The screening of plant-derived compounds with anti-cancer properties is a promising strategy to meet the growing need for new, safe and effective anti-cancer drugs. Justicidin B is a plants secondary metabolite that displays anti-cancer properties in several tumor cells. Therefore, it represents a good candidate. We used the 3R-compliant organism Caenorhabditis elegans to evaluate the safety of justicidin B produced by in vitro-grown adventitious roots of Linum lewisii. We showed that a dose of 100 µg/mL justicidin B does not affect worm vitality in either short-term or chronic administration; in contrast, the 200 µg/mL dose induces a lifespan reduction, but only in short-term daily treatment. We attributed this effect to its accumulation in lipofuscin granules in the pharynx as observed through confocal analysis. HPLC analysis confirmed the higher accumulation justicidin B with a 200 µg/mL dose but also revealed the presence of metabolic derivatives that could be responsible for the toxicity. We also demonstrated that the 100 µg/mL dose does not affect worm fertility or development. Our results highlight the safety of justicidin B, supporting its employment in cancer therapy, and encourage the use of a C. elegans model as an appropriate tool to assess compounds’ toxicity before moving to more complex organisms.

Elderly individuals are more vulnerable to disease due to their increased frailty. Emerging evidence highlights the potential of probiotics as geroprotective agents by maintaining gut health and modulating key physiological processes involved in aging, such as inflammation, cognitive functions, and metabolism. Here, we investigated the geroprotective potential of four probiotic strains (Lacticaseibacillus paracasei LPC1114, Limosilactobacillus reuteri PBS072, Bifidobacterium breve BB077, and Bifidobacterium animalis subsp. lactis BL050) using Caenorhabditis elegans as an aging model. Mid-life healthspan parameters were assessed, including lifespan, motility, ROS levels, lipofuscin accumulation, and cognitive capabilities. The probiotics exhibited strain-specific effects. L. reuteri PBS072 and B. lactis BL050 significantly increased locomotion by 20% and decreased ROS levels by 70% and 30% respectively, suggesting enhanced oxidative stress response and neuromuscular maintenance. B. breve BB077, L. paracasei LPC1114, and L. reuteri PBS072 enhanced associative learning performance, whereas B. lactis BL050 improved chemotactic response. Notably, only L. paracasei LPC1114 and L. reuteri PBS072 extended the maximum lifespan by 4 and 5 days, respectively, an effect mediated by the longevity-related genes skn1, sir2.1, and daf16. Our findings highlight the multifaceted, strain-specific geroprotective properties of probiotics and support their potential as microbiome-based interventions to promote healthy aging.