Biological activity of volatiles produced by the strains of two Pseudomonas and two Serratia species.

Volatile compounds emitted by bacteria can play a significant role in interacting with microorganisms, plants, and other organisms. In this work, we studied the effect of total gaseous mixtures of organic as well as inorganic volatile compounds (VCs) and individual pure volatile organic compounds (VOCs: ketones 2-nonanone, 2-heptanone, 2-undecanone, a sulfur-containing compound dimethyl disulfide) synthesized by the rhizosphere Pseudomonas chlororaphis 449 and Serratia plymuthica IC1270 strains, the soil-borne strain P. fluorescens B-4117, and the spoiled meat isolate S.

Long-Term Antimicrobial Performance of Textiles Coated with ZnO and TiO Nanoparticles in a Tropical Climate.

This paper reports the results of the large-scale field testing of composite materials with antibacterial properties in a tropical climate. The composite materials, based on a cotton fabric with a coating of metal oxide nanoparticles (TiO2 and/or ZnO), were produced using high-power ultrasonic treatment. The antibacterial properties of the materials were studied in laboratory tests on solid and liquid nutrient media using bacteria of different taxonomic groups (Escherichia coli, Chromobacterium violaceum, Pseudomonas chlororaphis).

Effects of Volatile Organic Compounds on Biofilms and Swimming Motility of .

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 strains and swimming motility, which can play an important role in the formation of biofilms.

The Effect of Volatile Organic Compounds on Different Organisms: Agrobacteria, Plants and Insects.

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 , plants, and fruit flies .

The Role of SprIR Quorum Sensing System in the Regulation of 94 Invasion.

The bacteria 94 have a LuxI/LuxR type QS system consisting of AHL synthase SprI and the regulatory receptor SprR. We have previously shown that inactivation of the AHL synthase gene resulted in an increase in the invasive activity of correlated with an increased bacterial adhesion. In the present work, the effects of inactivation of the receptor SprR are studied.

Invasion of Serratia proteamaculans is regulated by the sprI gene encoding AHL synthase.

Quorum Sensing (QS) system regulates gene expression in response to a change in the density of the bacterial population. Facultative pathogen Serratia proteamaculans 94 has a LuxI/LuxR type QS system consisting of regulatory protein SprR and AHL synthase SprI. Invasive activity of these bacteria appears at the stationary growth phase corresponding to a maximal density of the bacterial population in vitro.

The Mode of Action of Cyclic Monoterpenes (-)-Limoneneand (+)-α-Pinene on Bacterial Cells.

A broad spectrum of volatile organic compounds' (VOCs') biological activities has attracted significant scientific interest, but their mechanisms of action remain little understood. The mechanism of action of two VOCs-the cyclic monoterpenes (-)-limonene and (+)-α-pinene-on bacteria was studied in this work. We used genetically engineered bioluminescent strains harboring stress-responsive promoters (responsive to oxidative stress, DNA damage, SOS response, protein damage, heatshock, membrane damage) fused to the genes of We showed that (-)-limonene induces the P and P promoters due to the formation of reactive oxygen species and, as a result, causes damage to DNA (SOSresponse), proteins (heat shock), and membrane (increases its permeability).

Four New Genes of Cyanobacterium PCC 7942 Are Responsible for Sensitivity to 2-Nonanone.

Microbial volatile organic compounds (VOCs) are cell metabolites that affect many physiological functions of prokaryotic and eukaryotic organisms. Earlier we have demonstrated the inhibitory effects of soil bacteria volatiles, including ketones, on cyanobacteria. Cyanobacteria are very sensitive to ketone action.

SprI/SprR Quorum Sensing System of 94.

In this study, we investigated the quorum sensing (QS) regulatory system of the psychrotrophic strain 94 isolated from spoiled refrigerated meat. The strain produced several -acyl--homoserine-lactone (AHL) QS signal molecules, with -(3-oxo-hexanoyl)--homoserine lactone and -(3-hydroxy-hexanoyl)--homoserine lactone as two main types. The and genes encoding an AHL synthase and a receptor regulatory protein, respectively, were cloned and sequenced.

New Evidence for Ag-Sputtered Materials Inactivating Bacteria by Surface Contact without the Release of Ag Ions: End of a Long Controversy?

The study provides new evidence for Ag-coated polyester (PES) mediating inactivation by way of genetically engineered (without porins, from now denoted porinless bacteria). This allows the quantification of the bactericidal kinetics induced by the Ag surface without the intervention of Ag ions. Bacterial inactivation mediated by Ag-PES was seen to be completed within 60 min.

Inhibition of cyanobacterial photosynthetic activity by natural ketones.

Microbial volatiles have a significant impact on the physiological functions of prokaryotic and eukaryotic organisms. Various ketones are present in volatile mixtures produced by plants, bacteria, and fungi. Our earlier results demonstrated the inhibitory effects of soil bacteria volatiles, including ketones, on cyanobacteria.

Femtosecond Spectroscopy of Au Hot-Electron Injection into TiO₂: Evidence for Au/TiO₂ Plasmon Photocatalysis by Bactericidal Au Ions and Related Phenomena.

In the present work, we provide evidence for visible light irradiation of the Au/TiO₂ nanoparticles' surface plasmon resonance band (SPR) leading to electron injection from the Au nanoparticles to the conduction band of TiO₂. The Au/TiO₂ SPR band is shown to greatly enhance the light absorption of TiO₂ in the visible region. Evidence is presented for the light absorption by the Au/TiO₂ plasmon bands leading to the dissolution of Au nanoparticles.

Evidence for differentiated ionic and surface contact effects driving bacterial inactivation by way of genetically modified bacteria.

New evidence is presented for the bacterial inactivation of E. coli presenting normal porins on sputtered Ag-Cu surfaces compared with similar E. coli porinless bacteria.

Ketones 2-heptanone, 2-nonanone, and 2-undecanone inhibit DnaK-dependent refolding of heat-inactivated bacterial luciferases in Escherichia coli cells lacking small chaperon IbpB.

Many bacteria, fungi, and plants produce volatile organic compounds (VOCs) emitted to the environment. Bacterial VOCs play an important role in interactions between microorganisms and in bacterial-plant interactions. Here, we show that such VOCs as ketones 2-heptanone, 2-nonanone, and 2-undecanone inhibit the DnaKJE-ClpB bichaperone dependent refolding of heat-inactivated bacterial luciferases.

Influence of volatile organic compounds emitted by Pseudomonas and Serratia strains on Agrobacterium tumefaciens biofilms.

The ability to form biofilms plays an important role in bacteria-host interactions, including plant pathogenicity. In this work, we investigated the action of volatile organic compounds (VOCs) produced by rhizospheric strains of Pseudomonas chlororaphis 449, Pseudomonas fluorescens B-4117, Serratia plymuthica IC1270, as well as Serratia proteamaculans strain 94, isolated from spoiled meat, on biofilms formation by three strains of Agrobacterium tumefaciens which are causative agents of crown-gall disease in a wide range of plants. In dual culture assays, the pool of volatiles emitted by the tested Pseudomonas and Serratia strains suppressed the formation of biofilms of A.

Effect of plant phenolic compounds on biofilm formation by Pseudomonas aeruginosa.

In the natural environment, bacteria predominantly exist in matrix-enclosed multicellular communities associated with various surfaces, referred to as biofilms. Bacteria in biofilms are extremely resistant to antibacterial agents thus causing serious problems for antimicrobial therapy. In this study, we showed that different plant phenolic compounds, at concentrations that did not or weakly suppressed bacterial growth, increased the capacity of Pseudomonas aeruginosa PAO1 to form biofilms.

Quorum-sensing quenching by rhizobacterial volatiles.

We show that volatile organic compounds (VOCs) produced by rhizospheric strains Pseudomonas fluorescens B-4117 and Serratia plymuthica IC1270 may act as inhibitors of the cell-cell communication quorum-sensing (QS) network mediated by N-acyl homoserine lactone (AHL) signal molecules produced by various bacteria, including strains of Agrobacterium, Chromobacterium, Pectobacterium and Pseudomonas. This quorum-quenching effect was observed when AHL-producing bacteria were treated with VOCs emitted by strains B-4117 and IC1270 or with dimethyl disulfide (DMDS), the major volatile produced by strain IC1270. LC-MS/MS analysis revealed that treatment of strains Pseudomonas chlororaphis 449, Pseudomonas aeruginosa PAO1 or Ps.

Effect of nitrofurans and NO generators on biofilm formation by Pseudomonas aeruginosa PAO1 and Burkholderia cenocepacia 370.

Antibacterial drugs in the nitrofuran series, such as nitrofurazone, furazidin, nitrofurantoin and nifuroxazide, as well as the nitric oxide generators sodium nitroprusside and isosorbide mononitrate in concentrations that do not suppress bacterial growth, were shown to increase the capacity of pathogenic bacteria Pseudomonas aeruginosa PAO1 and Burkholderia cenocepacia 370 to form biofilms. At 25-100microg/ml, nitrofurans 2-2.5-fold enhanced biofilm formation of P.

Aspartyl-tRNA synthetase is the target of peptide nucleotide antibiotic Microcin C.

Microcin C is a ribosome-synthesized heptapeptide that contains a modified adenosine monophosphate covalently attached to the C-terminal aspartate. Microcin C is a potent inhibitor of bacterial cell growth. Based on the in vivo kinetics of inhibition of macromolecular synthesis, Microcin C targets translation, through a mechanism that remained undefined.

Microcin C51 plasmid genes: possible source of horizontal gene transfer.

Microcin C51 (MccC51) is an antimicrobial nucleotide-heptapeptide produced by a natural Escherichia coli strain. A 5.7-kb fragment of the pC51 plasmid carrying the genes involved in MccC51 production, secretion, and self-immunity was sequenced, and the genes were characterized.