This study investigated the essential oils (EOs) from leaf, bark, and fruit of Mespilodaphne cymbarum (Kunth) Trofimov (Lauraceae), focusing on their chemical composition and antimicrobial and antibiofilm activities. EOs were extracted from plants collected in the Amazon during dry and flood seasons and analyzed by gas chromatography–mass spectrometry. Although chemical differences were evident among plant organs and chemotypes, the influence of seasonality was not pronounced. Fruit EO was dominated by α- and β-santalene and limonene. Bark EO was rich in phenylpropanoids, including methyl eugenol, myristicin, and elemicin. Leaf EO showed the greatest metabolic diversity, with chemotype-specific variations. Leaf and bark EOs demonstrated superior antibacterial and antibiofilm activities compared to fruit EO, especially against Gram-positive bacteria such as Staphylococcus epidermidis, Staphylococcus aureus, and Micrococcus luteus. Chemotype-1 leaf and bark EOs inhibited S. epidermidis biofilm formation, while chemotype-2 reduced bacterial growth. The leaf EOs from both chemotypes reduced bacterial growth against S. aureus, and bark EO decreased biofilm formation. All leaf and bark EOs showed antibiofilm activity against M. luteus. These findings highlight the potential of M. cymbarum EOs as natural sources of bioactive compounds and emphasize the importance of chemotype and plant organ selection for optimized applications.

The genus Shewanella is renowned for its metabolic versatility and role in extracellular electron transfer (EET). This study characterizes Shewanella sp. (REG000848), a lineage isolated from the South Atlantic Blue Amazon. Phylogenomic metrics (ANI < 85% and dDDH < 27%) reveal that REG000848 is a genetically divergent lineage, exhibiting unique adaptations to marine stressors. The strain demonstrated exceptional physiological resilience, maintaining growth at temperatures up to 45°C, salinity levels of 12% NaCl, and a pH range of 4.5–10.0, significantly exceeding the thresholds of the model S. oneidensis MR-1. Genomic analysis identified a robust Mtr respiratory machinery, with multiple paralogs of the MtrB/PioB family and deca-heme cytochromes (MtrC and OmcA), providing the framework for its bioelectrogenic potential. Pangenomic analysis defining REG000848 as a specialized ecotype within the Southern Blue Amazon. In Microbial Fuel Cells (MFCs), the lineage achieved an immediate Open-Circuit Voltage (OCV) of 250 mV, suggesting a biofilm-independent electron transfer mechanism. These findings underscore the South Atlantic as a strategic reservoir of genetic resources, positioning Shewanella sp. (REG000848) as a promising bio-platform for sustainable energy and industrial biotechnology in processes that are usually stressful for most microorganisms.

This study investigated the essential oils (EOs) from leaves, bark, and fruits of Mespilodaphne cymbarum (Kunth) Trofimov (Lauraceae), characterizing their chemical composition and evaluating their antimicrobial and antibiofilm activities. EOs were extracted from plants collected in the Amazon during dry and flood seasons and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Although chemical differences were evident among plant organs and chemotypes, the influence of seasonality was not pronounced. Major metabolites of fruits EO were α- and β-santalene and limonene. Bark EO was rich in phenylpropanoids, including methyl eugenol, myristicin and elemicin. Leaf EOs showed the greatest metabolic diversity, with chemotype-specific variations. Essential oils from leaves and bark demonstrated superior antibacterial and antibiofilm activities compared to fruit oils, especially against Gram-positive bacteria. Differences among plant organs and chemotypes were observed, with leaf oils showing strong inhibition of biofilm formation and bark oils exhibiting broader antibacterial effects. These findings highlight the potential of M. cymbarum EOs as a natural source of bioactive compounds and emphasizing the importance of chemotype and plant organ selection for optimized applications.

Pseudoalteromonas species are ecologically versatile marine bacteria widely recognized for their capacity to synthesize diverse bioactive metabolites and psychrophilic enzymes with biotechnological relevance. Here, we present a comprehensive comparative genomic analysis of 53 reference genomes to elucidate the dynamics, functional diversity, and biosynthetic potential of this genus. Reference genomes representing each deposited species were selected in order to avoid bias associated with unequal numbers of genomes per species. Pangenome reconstruction revealed an open structure comprising a small core genome (1,350 gene families) and a large proportion of accessory and strain-specific genes, reflecting extensive genomic plasticity. Functional annotation indicated that accessory regions are enriched for genes involved in secondary metabolism, stress adaptation, and environmental resilience. Notably, biosynthetic gene cluster (BGC) mining uncovered a rich repertoire of potentially novel RiPPs and other secondary metabolite clusters, underscoring Pseudoalteromonas as a promising source of unexplored bioactive compounds. Statistical analyses revealed that pigmented strains harbor significantly higher numbers of BGCs compared to non-pigmented strains, while only a weak and non-significant correlation was observed between BGC abundance and carbohydrate-active enzyme (CAZyme) content. No significant effect of the isolation source was detected on either BGC or CAZyme distributions. Together, these findings provide new insights into the genomic basis of ecological adaptation and metabolic diversification in Pseudoalteromonas , supporting the role of pigmentation as a proxy for enhanced biosynthetic potential, while carbohydrate utilization capabilities evolve more independently and offering a framework for targeted bioprospecting of marine-derived metabolites with industrial and environmental applications.