Adaptations of Biofilms to Oxidative Stress Induced by Copper(II) Oxide Nanoparticles.

Copper(II) oxide nanoparticles (CuO NPs) are used in different industries and agriculture, thus leading to their release to the environment, which raises concerns about their ecotoxicity and biosafety. The main toxicity mechanism of nanometals is oxidative stress as a result of the formation of reactive oxygen species caused by metal ions released from nanoparticles. Bacterial biofilms are more resistant to physical and chemical factors than are planktonic cells due to the extracellular polymeric matrix (EPM), which performs a protective function.

Draft genome sequence of propane- and butane-oxidizing IEGM 333 able to accumulate cesium.

A genome of IEGM 333 was sequenced and annotated. This bacterium had pronounced propane- and butane-oxidizing and cesium-accumulating activities. The obtained sequence could be used to reveal the genetic mechanisms of these activities and efficiently exploit the biotechnological potential of propanotrophic .

Exposure to metal nanoparticles changes zeta potentials of cells.

Nanoparticles (NPs) of transition metals and their oxides are widely used in industries and exhibit diverse biological activities - from antimicrobial to growth promoting and regulating biofilms. In this study, the concentration-dependent effects of negatively charged metal and metal oxide NPs on the viability and net surface charge of cells were revealed. Our hypothesis that zeta potential values of bacterial cells approach the zeta potential of NPs with an increase in the concentration of nanoparticles was statistically validated, thus suggesting the accumulation of nanoparticles on the cell surface.

Biosynthesis and Characterization of Gold Nanoparticles Produced Using Actinobacteria at Elevated Chloroauric Acid Concentrations.

The growing industrial and medical use of gold nanoparticles (AuNPs) requires environmentally friendly methods for their production using microbial biosynthesis. The ability of actinobacteria of the genus to synthesize AuNPs in the presence of chloroauric acid (HAuCl) was studied. The effect of elevated (0.

Effects of Nickel Nanoparticles on Cell Surface Morphology and Nanomechanical Properties.

Nickel nanoparticles (NPs) are used for soil remediation and wastewater treatment due to their high adsorption capacity against complex organic pollutants. However, despite the growing use of nickel NPs, their toxicological towards environmental bacteria have not been sufficiently studied. Actinobacteria of the genus are valuable bioremediation agents degrading a range of harmful and recalcitrant chemicals.

Potential risks of antibiotic resistant bacteria and genes in bioremediation of petroleum hydrocarbon contaminated soils.

Bioremediation represents a sustainable approach to remediating petroleum hydrocarbon contaminated soils. One aspect of sustainability includes the sourcing of nutrients used to stimulate hydrocarbon-degrading microbial populations. Organic nutrients such as animal manure and sewage sludge may be perceived as more sustainable than conventional inorganic fertilizers.

Preparation of novel ring-A fused azole derivatives of betulin and evaluation of their cytotoxicity.

An efficient scheme to synthesize novel ring-A fused heterocyclic derivatives of betulin was developed. The starting reaction of this synthesis was one-pot selective bacterial oxidation of betulin to betulone used as the key compound to synthesize the substituted azoles such as C(2)-C(3)-fused 1,2,3-triazoles, oxazoles and 1,2,4-triazine, as well as C(1)-C(2)-fused isoxazoles. The semi-synthetic compounds were screened for their cytotoxic activity against human cancer cell lines A549, HCT 116, HEp-2, MS and RD TE32 with use of the photometric MTT assays.

Diverse effects of a biosurfactant from Rhodococcus ruber IEGM 231 on the adhesion of resting and growing bacteria to polystyrene.

This study evaluated the effects of a trehalolipid biosurfactant produced by Rhodococcus ruber IEGM 231 on the bacterial adhesion and biofilm formation on the surface of polystyrene microplates. The adhesion of Gram-positive (Arthrobacter simplex, Bacillus subtilis, Brevibacterium linens, Corynebacterium glutamicum, Micrococcus luteus) and Gram-negative (Escherichia coli, Pseudomonas fluorescencens) bacteria correlated differently with the cell hydrophobicity and surface charge. In particular, exponentially growing bacterial cells with increased hydrophobicities adhered stronger to polystyrene compared to more hydrophilic stationary phase cells.

Oil spill problems and sustainable response strategies through new technologies.

Crude oil and petroleum products are widespread water and soil pollutants resulting from marine and terrestrial spillages. International statistics of oil spill sizes for all incidents indicate that the majority of oil spills are small (less than 7 tonnes). The major accidents that happen in the oil industry contribute only a small fraction of the total oil which enters the environment.

PERN: an EU-Russia initiative for rhizosphere microbial resources.

Millions of microbial taxa inhabit the rhizosphere and could be used as biofertilizers, biopesticides, and/or for bioremediation. Only a fraction of these microbes have been described and/or are being utilized. Most are dispersed in collections, but coordination of their accessibility and availability is challenging.

Trehalolipid biosurfactants from nonpathogenic Rhodococcus actinobacteria with diverse immunomodulatory activities.

Actinobacteria of the genus Rhodococcus produce trehalolipid biosurfactants with versatile biochemical properties and low toxicity. In recent years, these biosurfactants are increasingly studied as possible biomedical agents with expressed immunological activities. Applications of trehalolipids from Rhodococcus, predominantly cell-bound, in biomedicine are also attractive because their cost drawback could be less significant for high-value products.

Draft Genome Sequence of Propane- and Butane-Oxidizing Actinobacterium Rhodococcus ruber IEGM 231.

We report a draft genome sequence of Rhodococcus ruber IEGM 231, isolated from a water spring near an oil-extracting enterprise (Perm region, Russian Federation). This sequence provides important insights into the genetic mechanisms of propane and n-butane metabolism, organic sulfide and beta-sitosterol biotransformation, glycolipid biosurfactant production, and heavy metal resistance in actinobacteria.

Drotaverine hydrochloride degradation using cyst-like dormant cells of Rhodococcus ruber.

This work has a focus on adaptive capabilities of the actinobacterium Rhodococcus ruber IEGM 326 to cope with drotaverine hydrochloride (DH), a known pharmaceutical pollutant. Cultivation of R. ruber in a nitrogen-limited medium with incubation at the ambient temperature resulted in the formation of cyst-like dormant cells (CLDCs).

Assessment of bacterial resistance to organic solvents using a combined confocal laser scanning and atomic force microscopy (CLSM/AFM).

Using combined confocal laser scanning and atomic force microscopy (CLSM/AFM), bacterial viability under organic solvent stress was assessed at single cell level. Solvent-exposed bacteria stained with the LIVE/DEAD BacLight fluoresced green or red, allowing viable and dead cell discrimination. However, with toluene, butanol and acetonitrile, dually fluorescent cells appeared having compromised cell membranes.

Turning Russian specialized microbial culture collections into resource centers for biotechnology.

Specialized nonmedical microbial culture collections contain unique bioresources that could be useful for biotechnology companies. Cooperation between collections and companies has suffered from shortcomings in infrastructure and legislation, hindering access to holdings. These challenges may be overcome by the transformation of collections into national bioresource centers and integration into international microbial resource networks.

Simultaneous species-specific PCR detection and viability testing of poly(vinyl alcohol) cryogel-entrapped Rhodococcus spp. after their exposure to petroleum hydrocarbons.

A method of simultaneous species-specific PCR detection and viability testing of poly(vinyl alcohol) cryogel-entrapped Rhodococcus spp. was developed that allowed the estimation of immobilized Rhodococcus opacus and Rhodococcus ruber survival after their exposure to petroleum hydrocarbon mixture. Spectrophotometric INT assay revealed high tolerance of gel-immobilized rhodococci to petroleum hydrocarbons, while among two Rhodococcus strains studied, R.

Biosurfactant-enhanced immobilization of hydrocarbon-oxidizing Rhodococcus ruber on sawdust.

Immobilization of microorganisms on/in insoluble carriers is widely used to stabilize functional activity of microbial cells in industrial biotechnology. We immobilized Rhodococcus ruber, an important hydrocarbon degrader, on biosurfactant-coated sawdust. A biosurfactant produced by R.

In vitro cytokine stimulation assay for glycolipid biosurfactant from Rhodococcus ruber: role of monocyte adhesion.

Glycolipid biosurfactant (GLB) from Rhodococcus ruber IEGM 231 was found to stimulate tumor necrosis factor-α (TNF-α), interleukin (IL) -1β and IL-6 production when applied as an ultrasonic emulsion to the adherent human peripheral blood monocyte culture. However, a lack of cytokine-stimulating activity was registered with the GLB applied as a hydrophobic film coating in 24-well culture plates, indicating that it may have been due to its inhibitory effect on monocyte adhesion. The mode of GLB application may therefore play an important role in in vitro assay of immunostimulatory activity of this compound as well as other bacterial glycolipids.

Selective adsorption of hydrocarbon-oxidizing Rhodococcus cells in a column with hydrophobized poly(acrylamide) cryogel.

A method for selective adsorption of Rhodococcus cells in the column with hydrophobized poly(acrylamide) cryogel (cryoPAAG) was developed that allowed rhodococci separation from mixed bacterial populations and their effective concentration within a sponge-like gel matrix. Hydrophobization of cryoPAAG using the n-dodecane graft (C12) was performed to enhance the adhesion of Rhodococcus cells to the cryogel; this was suggested by our finding that alkanotrophic rhodococci possess high adhesive activity (91-98%) towards n-alkanes, whereas other Gram-positive and Gram-negative bacteria tested did not adhere strongly to hydrocarbons. The selective index of the hydrophobic C12-cryoPAAG column for Rhodococcus cells was 72% that ensured their separation from complex bacterial cultures.

Hydrophobised sawdust as a carrier for immobilisation of the hydrocarbon-oxidizing bacterium Rhodococcus ruber.

Pine sawdust treated by a series of hydrophobising agents (drying oil, organosilicon emulsion, n-hexadecane and paraffin) was examined as carrier for adsorption immobilisation of hydrocarbon-oxidizing bacterial cells Rhodococcus ruber. It was shown that hydrophobising agents based on drying oil turned out to be optimal (among the other modifiers examined) for the preparation of sawdust carriers suitable for the efficient immobilisation. The results obtained demonstrate promising possibilities in developing a wide range of available and cheap, biodegradable cellulose-containing carriers that possess varying surface hydrophobicity.

Immobilization of hydrocarbon-oxidizing bacteria in poly(vinyl alcohol) cryogels hydrophobized using a biosurfactant.

A simple biosurfactant-based hydrophobization procedure for poly(vinyl alcohol) (PVA) cryogels was developed allowing effective immobilization of hydrocarbon-oxidizing bacteria. The resulting partially hydrophobized PVA cryogel granules (granule volume 5 microl) contained sufficient number (6.5 x 10(3)) of viable bacterial cells per granule, possessed high mechanical strength and spontaneously located at the interface in water-hydrocarbon system.

Effect of biosurfactants on crude oil desorption and mobilization in a soil system.

Microbially produced biosurfactants were studied to enhance crude oil desorption and mobilization in model soil column systems. The ability of biosurfactants from Rhodococcus ruber to remove the oil from the soil core was 1.4-2.

Methods evaluating vanadium tolerance in bacteria isolated from crude oil contaminated land.

Investigations into bacterial responses to vanadium are rare, and in this study were initiated by isolating cultures from crude oil contaminated soil from Russia and Saudi Arabia. Addition of vanadyl sulphate and vanadium pentoxide created acid conditions in the media whilst sodium metavanadate and sodium orthovanadate produced neutral and alkaline effects, respectively. Buffers were introduced for wider comparison of the sample set treatments and to distinguish between the effects of pH and compound toxicity.