Molecular hybridization, which consists of the combination of two or more pharmacophores into a single molecule, is an innovative approach in drug design to afford new chemical entities with enhanced biological activity. In the present study, this strategy was pursued to develop a new series of 6,7-dimethoxy-4-piperazinylquinoline-3-carbonitrile derivatives (5a–k) with potential antibiotic activity by combining the quinoline, the piperazinyl, and the benzoylamino moieties, three recurrent frameworks in antimicrobial research. Initial in silico evaluations were conducted on the designed compounds, highlighting favorable ADMET and drug-likeness properties, which were synthesized through a multistep strategy, isolated, and fully characterized. The whole set was tested in vitro against Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 10145 representative Gram-positive and Gram-negative strains, respectively. Notably, 5k exhibited potent and selective activity against S. aureus (MIC 10 μM), with a dose- and time-dependent response and capability to affect cell membrane integrity. On the other hand, no significant activity was observed against P. aeruginosa. Further in silico docking and molecular dynamics studies highlighted strong interactions of 5k with bacterial enzymes, such as tyrosyl-tRNA synthetase, pyruvate kinase, and DNA gyrase B, suggesting potential modes of action. These findings underscore the value of the hybridization approach in producing new antimicrobial agents, guiding future optimization for broader-spectrum activity.

Bacterial extracellular vesicles (BEVs) are nanosized (10–400 nm), membrane-enclosed particles naturally secreted by both Gram-negative and Gram-positive bacteria. Initially characterized as virulence factors in pathogenic species, BEVs are now recognized as multifunctional entities with significant biotechnological potential. Their cargo—comprising proteins, lipids, nucleic acids, and metabolites—enables diverse biological activities, including immune modulation, epithelial barrier protection, stress tolerance, and intercellular communication. Recent studies have highlighted BEVs from biotechnologically relevant bacteria—such as plant growth-promoting rhizobacteria, lactic acid bacteria, bifidobacteria, cyanobacteria, bacilli, and streptomycetes—for their different roles in biological and ecological interactions. These properties underpin emerging applications in health, agriculture, and bioprocessing, including next-generation postbiotics, vaccine platforms, drug and RNA delivery systems, and novel plant biostimulants. However, major challenges persist, particularly low production yields, variability in cargo composition, and scalability. Addressing these limitations requires a deeper understanding of vesiculation mechanisms and the development of process-oriented strategies for BEV recovery and purification. This review synthesizes recent advances in genetic analysis, physiological modulation, physicochemical stimuli, and bioprocess optimization aimed at enhancing BEV production and stabilizing cargo profiles, providing a comprehensive overview of approaches to unlock the full potential of BEVs as versatile biotechnological tools.

Hydrothermal springs (HTSs) are unique environments characterized by the emergence of geothermally heated groundwater that often releases large amounts of dissolved minerals. Despite the interest in HTSs, the microbial composition of these sites remains largely under-explored, particularly concerning the interactions between marine invertebrates and microorganisms. The shallow HTSs near the west coast of Sicily (Italy), with a constant temperature of 31 °C throughout the year, host two invertebrates: the nudibranch Peltodoris atromaculata (P. atromaculata) and the sponge Petrosia ficiformis (P. ficiformis). Using Next-Generation Sequencing (NGS) of the bacterial 16S rRNA gene marker, the bacterial communities of these invertebrates were analyzed. Microbial diversity was higher in the P. atromaculata mantle and in P. ficiformis than in the P. atromaculata gut, with notable differences in families such as Caldilineaceae, Endozoicomonadaceae, Alteromonadaceae, and Enterobacteriaceae, showing abundance variations among the samples. Unique bacterial signatures, including Mycoplasmataceae, Endozoicomonadaceae, and Alteromonadaceae in the gut and Enterobacteriaceae in the mantle of P. atromaculata, were also identified. These findings provide valuable insights into the bacterial diversity of these two marine invertebrates, which are recognized as bioindicators of environmental conditions.

Marine hydrothermal ecosystems represent extreme environments connected to submarine volcanic areas characterized by vents, having high temperatures and particular chemical compositions. The hydrothermal marine system of Panarea, located in one of the seven small islands belonging to the Aeolian Archipelago (southern Tyrrhenian Sea), is characterized by a range of vents exhibiting diverse physical and chemical conditions. We aimed to analyze the microbial community of a peculiar hot spring belonging to the Panarea hydrothermal field, known as “Black Point” (BP), in two separate sampling expeditions (May and August). Our results demonstrated that the chemical–physical variations within this hydrothermal vent, such as temperature fluctuations, mineral content, and hydrothermal fluid dynamics, play a role in shaping the structure and diversity of microbial communities. The differences between the two sampling expeditions suggest that seasonal changes, i.e., in temperature, pH, and redox potential (Eh), could drive microbial community shifts over time.