Nonsteroidal Anti-inflammatory Drugs as Emerging Contaminants

Microbiology - Nonsteroidal anti-inflammatory drugs (NSAIDs) are a group of pharmaceuticals widely used for medical and veterinary purposes. NSAIDs have been found in nanograms and micrograms in...     

Reduction of Copper Ion Phytotoxicity Using Rhodococcus-Biosurfactants

Biology Bulletin - Abstract—The effect of copper on the germination of seeds of several agricultural crops, such as common vetch (Vicia saliva L.), white mustard (Sinapis alba L.), and...     

DELAYED URIC ACID ACCUMULATION IN PLASMA PROVIDES ADDITIONAL ANTI-OXIDANT PROTECTION AGAINST IRON-TRIGGERED OXIDATIVE STRESS AFTER A WINGATE TEST

Reactive oxygen species are produced during anaerobic exercise mostly by Fe ions released into plasma and endothelial/muscle xanthine oxidase activation that generates uric acid (UA) as the endpoint metabolite. Paradoxically, UA is considered a major antioxidant by virtue of being able to chelate pro-oxidative iron ions. This work aimed to evaluate the relationship between UA and plasma markers of oxidative stress following the exhaustive Wingate test. Plasma samples of 17 male undergraduate students were collected before, 5 and 60 min after maximal anaerobic effort for the measurement of total iron, haem iron, UA, ferric-reducing antioxidant activity in plasma (FRAP), and malondialdehyde (MDA, biomarker of lipoperoxidation). Iron and FRAP showed similar kinetics in plasma, demonstrating an adequate pro-/antioxidant balance immediately after exercise and during the recovery period (5–60 min). Slight variations of haem iron concentrations did not support a relevant contribution of rhabdomyolysis or haemolysis for iron overload following exercise. UA concentration did not vary immediately after exercise but rather increased 29% during the recovery period. Unaltered MDA levels were concomitantly measured. We propose that delayed UA accumulation in plasma is an auxiliary antioxidant response to post-exercise (iron-mediated) oxidative stress, and the high correlation between total UA and FRAP in plasma (R-Square = 0.636; p = 0.00582) supports this hypothesis.     

Biocatalytic synthesis of pharmacology perspective stigmast-4-en-3-one using rhodococci cells

Conditions for a directed biocatalytic oxidation of β-sitosterol to pharmacologically valuable stigmast-4-en-3-one using Rhodococcus actinobacteria were determined. It was shown that palmitic acid induced the cholesterol oxidase reaction and allowed for the decrease in the bioconversion process duration from 7 to 5 days. The maximum level of stigmast-4-ene-3-one formation was achieved using an additional growth substrate n-hexadecane. With increased concentrations of β-sitosterol (up to 2 g/l) an effective target product formation (80%) was achieved in the presence of Tween-80 and β-cyclodextrin. R. erythropolis strains were 1.5–2 times more active than R. ruber strains in catalyzing the β-sitosterol biotransformation process.     

Highly Efficient Biodegradation of Ecotoxic Dehydroabietic Acid by Resting Cells of Rhodococcus rhodochrous IEGM 107

Microbiology - The possibility of complete biodegradation of toxic dehydroabietic acid (DHA) at a high (more than 500 mg/L) concentration using resting cells of Rhodococcus rhodochrous IEGM 107...     

Effect of cultivation conditions on the adhesive activity of Rhodococcus cells towards n-Hexadecane

The effect of cultivation conditions (the composition, acidity, and salinity of the cultivation medium; temperature; and the hydrodynamic conditions of cultivation) on the adhesion of actinobacteria of the genus Rhodococcus to n-hexadecane has been investigated. A study performed showed that the adhesive activity of rhodococci depends on the composition of the cultivation medium and on the cultivation temperature. The possible mechanisms underlying the effect of growth conditions on the adhesion of rhodococci to liquid hydrocarbons and involving changes in the cell lipid content or the zeta potential of cells are addressed. Rhodococcal strains displaying high adhesive activity (80–90%) at a low temperature (18°C), high salinity (5.0% NaCl), and acidity (pH 6.0) of the cultivation medium have been selected as a result of the present work; these strains have a considerable potential for use in bioremediation of soil and water contaminated by hydrocarbons.     

A study of conformational states of substrates of isoform 3A4 of cytochrome P450

A multiconformational study of substrates for isoform 3A4 of cytochrome P450 with the use of the BiS/MC algorithm has been carried out. The use of this approach made it possible to determine the pseudo-atomic model of this cytochrome and to find the substrate conformers responsible for binding to the cytochrome. It was found that in most cases, the geometry of the conformer, which is bound to the isoform, substantially differs from the geometry of the global minimum conformer. It was shown that, as a rule, the mirror antipodes (enantioconformers) are characterized by different Michaelis constants. The quantitative relationship of the Michaelis constants with the parameters of interaction in the model complexes between the isoform 3A4 and substrates was determined. This dependence describes an experimental value of the Michaelis constant with a squared cross-validation correlation coefficient of 0.88, which was determined by leave-one-out cross-validation technique.     

The attitudes of riparian communities to the presence of water hyacinth in the Wouri River Basin,Douala, Cameroon

Since publication of the first record of Eichhornia crassipes in Cameroon in 1997, the weed has become highly invasive in the Wouri River Basin. Between June and September 2014, a socio-economic survey using participatory and qualitative methods was undertaken in the riparian villages of the Wouri River Basin to assess the perception of respondents to the presence of water hyacinth. The survey revealed that water hyacinth was a significant threat to activities along the river, which included fishing, sand extraction and river transportation. The presence of water hyacinth mats reduced catch rates of several common fish species, river transportation by 75%, and significantly reduced the income for sand extraction. Cameroon employs manual clearing of water hyacinth; however, respondents indicated they would consider other control methods, provided they do not have any negative impacts.     

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. ruber in the presence of liquid hydrocarbons was found to enhance rhodococcal adhesion to solid surfaces, and thus, it was used as a hydrophobizing agent to improve bacterial attachment to a sawdust carrier. Compared to previously used hydrophobizers (drying oil and n-hexadecane) and emulsifiers (methyl- and carboxymethyl cellulose, poly(vinyl alcohol), and Tween 80), Rhodococcus biosurfactant produced more stable and homogenous coatings on wood surfaces, thus resulting in higher sawdust affinity to hydrocarbons, uniform monolayer distribution of immobilized R. ruber cells (immobilization yield 29–30 mg dry cells/g), and twofold increase in hydrocarbon biooxidation rates compared to free rhodococcal cells. Two physical methods, i.e., high-resolution profilometry and infrared thermography, were applied to examine wood surface characteristics and distribution of immobilized R. ruber cells. Sawdust-immobilized R. ruber can be used as an efficient biocatalyst for hydrocarbon transformation and degradation.