The strain Achromobacter insolitus LCu2 isolated from the roots of alfalfa (Medicago sativa L.) utilized cinnamic acid and its methoxy derivatives (vanillic and ferulic acids) as the sole carbon source. Weak growth was observed with m-coumaric acid, but not on o- or p-coumaric acids. Growth on the cinnamic acid was slow and diauxic. The substrate decreased in the cultivation medium by 53%; the degradation efficiency during 14 days was 30 μg/mg wet weight. Despite the bactericidal effect of cinnamic acid, the culture A. insolitus LCu2 remained viable for a long time. Genomic analysis revealed two gene clusters (hca and mhp) responsible for the dihydroxylation of the phenyl ring (hcaA1A2CDB) and its subsequent cleavage to central metabolic products (mhpACDE), as well as a transcriptional regulator (hcaR) and a putative transporter (hcaT). A putative biochemical pathway for cinnamic acid degradation by the strain A. insolitus LCu2 was predicted using genomic data.

Nanomaterials are widely used in biomedical research as drug and antibody carriers, and some nanomaterials have been shown to exhibit antimicrobial activity. Previously, silver nanoclusters (AgNCs) were predicted to interact with the bacterial TolC protein, which is involved in the development of multidrug resistance in pathogens. In this study, glutathione-coated AgNCs were synthesized and characterized. Their toxicological properties were studied in a microplate assay against five bacterial strains, both as single components and in mixtures with heavy metal salts and antibiotics. The resulting AgNCs had a diameter of 2.2 ± 0.5 nm, with excitation and emission maxima of λ = 490 nm and λ = 638 nm, respectively. No significant growth inhibition was observed at the concentrations used in resistance modulation assays (≤2.5 µg/mL Ag), except for transient effects at very high concentrations. A decrease in bacterial resistance to copper (II) and cadmium (II) cations and the antibiotics erythromycin and levofloxacin was observed upon the addition of AgNCs containing 2.5 μg/mL silver to the nutrient medium. A dose-dependent effect of AgNCs on bacterial resistance to toxicants was established. Thus, nanoclusters can be considered as inhibitors of bacterial resistance to heavy metals and antibiotics, which may be useful in studying bacterial adaptation mechanisms and developing technologies for overcoming multidrug resistance in bacteria.

Phosphonates are alternative phosphorus sources for bacteria. The genome of Achromobacter insolitus strain LCu2 contains three predicted phn clusters of ABC-type phosphonate transporters into the cell. To understand the functional, evolutionary, and ecological role of the phn clusters, phylogenetic analysis of substrate-binding PhnD proteins from strain LCu2 with their homologs in other Achromobacter species and in closely related genera of the family Alcaligenaceae was carried out. The PhnD transporters formed three separate clusters, which indicated the differences in their structural composition. PhnD₁ and PhnD₂ were present in the genomes of all Achromobacter species and grouped separately from those of other members of the family Alcaligenaceae, which indicated vertical inheritance of the phnD₁ and phnD₂ genes and their involvement in the life-supporting processes. PhnD₃ was found in the genomes of seven Achromobacter species. The phnD₃ gene was probably acquired via horizontal transfer or duplication and is induced during adaptation to changing environmental conditions. Maintenance of three structurally different phn clusters of transporters is probably ecologically advantageous to A. insolitus LCu2, providing for phosphorus retrieval from synthetic and natural organophosphonates as well as other sources.

Phosphonates are alternative phosphorus sources for bacteria. The genome of Achromobacter insolitus strain LCu2 contains three predicted phn clusters of ABC-type phosphonate transporters into the cell. To understand the functional, evolutionary, and ecological role of the phn clusters, phylogenetic analysis of substrate-binding PhnD proteins from strain LCu2 with their homologs in other Achromobacter species and in closely related genera of the family Alcaligenaceae was carried out. The PhnD transporters formed three separate clusters, which indicated the differences in their structural composition. PhnD1 and PhnD2 were present in the genomes of all Achromobacter species and grouped separately from those of other members of the family Alcaligenaceae, which indicated vertical inheritance of the phnD1 and phnD2 genes and their involvement in the life-supporting processes. PhnD3 was found in the genomes of seven Achromobacter species. The phnD3 gene was probably acquired via horizontal transfer or duplication and is induced during adaptation to changing environmental conditions. Maintenance of three structurally different clusters of the phn transporters is probably ecologically advantageous to A. insolitus LCu2, providing for phosphorus retrieval from synthetic and natural organophosphonates as well as other sources.