Bacteria and fungi emit a huge variety of volatile organic compounds (VOCs) that can provide a valuable arsenal for practical use. However, the biological activities and functions of the VOCs are poorly understood. This work aimed to study the action of individual VOCs on the bacteria Agrobacterium tumefaciens, Arabidopsis thaliana plants, and fruit flies Drosophila melanogaster. VOCs used in the work included ketones, alcohols, and terpenes. The potent inhibitory effect on the growth of A. tumefaciens was shown for 2-octanone and isoamyl alcohol. Terpenes (−)-limonene and (+)-α-pinene practically did not act on bacteria, even at high doses (up to 400 µmol). 2-Butanone and 2-pentanone increased the biomass of A. thaliana at doses of 200–400 μmol by 1.5–2 times; 2-octanone had the same effect at 10 μmol and decreased plant biomass at higher doses. Isoamyl alcohol and 2-phenylethanol suppressed plant biomass several times at doses of 50–100 μmol. Plant seed germination was most strongly suppressed by isoamyl alcohol and 2-phenylethanol. The substantial killing effect (at low doses) on D. melanogaster was exerted by the terpenes and the ketones 2-octanone and 2-pentanone. The obtained data showed new information about the biological activities of VOCs in relation to organisms belonging to different kingdoms.

Volatile organic compounds (VOCs) emitted by bacteria play an important role in the interaction between microorganisms and other organisms. They can inhibit the growth of phytopathogenic microorganisms, modulate plant growth, and serve as infochemicals. Here, we investigated the effects of ketones, alcohols, and terpenes on the colony biofilms of plant pathogenic Agrobacterium tumefaciens strains and swimming motility, which can play an important role in the formation of biofilms. It was shown that 2-octanone had the greatest inhibitory effect on biofilm formation, acting in a small amount (38.7 g/m³). Ketone 2-butanone and unsaturated ketone β-ionone reduced the formation of biofilms at higher doses (145.2–580.6 and 387.1–1548.3 g/m³, respectively, up to 2.5–5 times). Isoamyl alcohol and 2-phenylethanol decreased the formation of biofilms at doses of 88.7 and 122.9 g/m³ by 1.7 and 5 times, respectively, with an increased effect at 177.4 and 245.9 g/m³, respectively. The agrobacteria cells in mature biofilms were more resistant to the action of ketones and alcohols. These VOCs also suppressed the swimming motility of agrobacteria; the radius of swimming zones decreased ~from 2 to 5 times. Terpenes (−)-limonene and (+)-α-pinene had no significant influence on the colony biofilms and swimming motility at the doses used. The results obtained represent new information about the effect of VOCs on biofilms and the motility of bacteria.

The screening of aqueous extracts of herbaceous plants that grow on the territory of the Russian Federation with their subsequent use for the biosynthesis of silver nanoparticles (SNPs) in...

Heavy metals and arsenic are environmental pollutants and have a negative effect on human health. Volatile organic compounds (VOCs) synthesized by bacteria

Whole-cell biosensors represent one of the tools used for assessing the effects of various agents on living cells. Here we have constructed and tested whole-cell lux-biosensors to detect membrane damage in both Gram-negative and Gram-positive bacteria using the stress-inducible promoter of the pspA gene from Escherichia coli and Bacillus subtilis fused to the lux genes from Photorhabdus luminescens. These biosensors increase their luminescence in response to treatment with a number of known membrane-damaging compounds, such as ethanol, Triton X-100, polymyxin B, dimethylsulfoxide (DMSO) and melittin. E. coli- and B. subtilis-based biosensors demonstrated differences in response to the action of the same membrane-damaging agent. Thus, ethanol and polymyxin B specifically induced the pspA promoter in both lux-biosensors, but the induction amplitude was higher in the E. coli. Triton X-100 and melittin specifically induced the pspA promoter exclusively in B. subtilis cells, while DMSO induced it only in E. coli cells. This indicates a difference in the stress response of the Psp system to membrane-damaging agents in E. coli and B. subtilis cells. Thus, we demonstrated the functionality and efficiency of the constructed lux-biosensors and, using them, showed that some of the tested compounds are able to specifically activate Psp stress response systems in case of membrane damage.