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A N Reshetilov

Publications and source records attributed to A N Reshetilov.

At least 37 records · Page 2Linked to original sources
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[Effect of various methods of immobilization on stability of a microbial biosensor based on Pseudomonas rathonis T during detection of surfactants].

The operating and storage stability of a receptor element of an amperometric biosensor based on the Pseudomonas rathonis strain T capable of degrading surfactants was tested. Microbial cells were immobilized by incorporation in gels (agar, agarose, and calcium-alginate), polyvinyl alcohol membrane, adhesion to the chromatographic paper GF/A, or by the cross-linking induced by glutaric aldehyde. Incorporation of microbial cells in agar gel provides the long-standing conservation of their activity and viability during measurements of high concentrations of surfactants and allows the receptory element of the biosensor to be rapidly recovered after the measurements.

Biosensing Techniques↗
PubMedDate not supplied

[Effect of conditions of culturing Pseudomonas rathonis T on characteristics of a biosensor for determining anionic surface-active agents].

The dependence of the sensitivity of a microbial biosensor of anionic surfactants (AS) on the growth phase of Pseudomonas rathonis T, a strain capable of degrading surfactants, was studied. Correlations were found between the optimum values of temperature and pH of microbial growth, substrate utilization, and functional performance of the microbial biosensor. These results allow the process of AS detection to be optimized.

Anions↗
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[Quantitative analysis of calibration dependence of biosensors].

Three-parameter Hill's equation, which is used in enzyme kinetics, was shown to applicable to calibration curves of both potentiometric (glucose, pesticides, urea, etc.) and amperometric (surfactants, biphenyl, etc.) biosensors. Possible causes of errors of analyte concentration measurements are discussed.

Biosensing Techniques↗
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[Development of biosensors for phenol determination from bacteria found in petroleum fields of West Siberia].

Nine Gram-negative bacterial strains, selected from 300 strains isolated from soils of the West Siberian petroliferous basin and growing on oil and oil products, consume phenol as a single carbon and energy source. The strains were used for the development of a sensor bioreceptor. The most active 32-I strain was shown to bear a plasmid responsible for phenol degradation. The plasmid-free derivative of this strain, 32-I-1, did not grow on phenol. The possibility of creating a model biosensor for phenol based on the plasmid-containing 32-I strain is considered. The detection limit for phenol was 5 microM. The optimum conditions for the sensor operation are: pH 7.4, 35 degrees C, and operation time 30 h.

Biosensing Techniques↗
PubMedDate not supplied

[Biosensor of the reactor type based on Rhodococcus erythropolis HL TM-1 cells for determining 2,4-dinitrophenol].

A model of a reactor-type biosensor based on the Rhodococcus erythropolis HL PM-1 was developed for amperometric detection of 2,4-dinitrophenol (2,4-DNP). The effects of the matrix material (agar and calcium alginate gels, ceramic support, and cellulose powder) on the biosensor signal concentration dependence, detection time, and biosensor stability were studied. In case of bacterial cells immobilized on cellulose powder, the lower limit of 2,4-DNP detection was 20 microM and the time of single analysis, the biosensor recovery included, was 30-50 min. In the continuous detection mode, the biosensor response was maintained at a stable level without biosensor inactivation for ten days. The biosensor can be used as an element of a complex analytical system for detecting nitroaromatic compounds in samples.

2,4-Dinitrophenol↗
PubMedDate not supplied

[Degradation of 2,4-dinitrophenol by free and immobilized cells of Rhodococcus erythropolis HL PM-1].

Degradation of 2,4-dinitrophenol (2,4-DNP) by the cells of Rhodococcus erythropolis HL PM-1 was studied. The enzymes involved in 2,4-DNP degradation were inducible, and their resynthesis took place during the process. Cell immobilization by embedding into agar gels decreased the degrader activity. Maximum rates of 2,4-DNP degradation by free and immobilized cells were 10.0 and 5.4 nmol/min per mg cells, respectively. The concentration dependence of 2,4-DNP degradation was typical of substrate inhibition kinetics. The immobilized cells were used in a model reactor designed for 2,4-DNP biodegradation. Its maximum capacity was 0.45 nmol/min per mg cells at a volumetric flow rate of 20 h-1. The reactor operated for 14 days without losing capacity; its half-lifetime equaled 16 days.

2,4-Dinitrophenol↗
PubMedDate not supplied

[Comamonas testosteroni strain TI as a potential base for a microbial sensor detecting surfactants].

Strain Comamonas testosteroni TI, capable of degrading the nonionic surfactant (NIS) nonylphenolethoxylate (OP-10), was used for constructing a pilot cellular biosensor. The lower NIS detection limit for the biosensor was 0.25 mg/l. We studied the substrate specificity of the biosensor with respect to a wide range of organic compounds: surfactants, polyaromatic compounds (PAC), carbohydrates, alcohols, etc. It was shown that the biosensor based on Comamonas testosteroni TI did not respond to glucose, which was an advantage over the formerly described biosensor based on Pseudomonas rathonis T. The amplitude of the sensor response remained stable for 10 days.

Biosensing Techniques↗
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[Microbial, enzymatic, and immune biosensors for ecological monitoring and control of biotechnological processes].

Results of the research performed at the Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, on designing immunobiosensors for detection of toxic compounds and microbial cells enzyme-based biosensors for detection of hydrocarbons and alcohols, and microbial biosensors for aromatic compounds, surfactants, and biological oxygen consumption are briefed. Parameters of the mediator electrodes involving microbial cells and data on the properties of microbial biofuel cells--devices based on biosensor principle and representing alternative sources of electric energy--are given.

Alcohols↗
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[Degradation of p-toluenesulfonate by immobilized Comamonas testosteroni BS1310 (pBS1010) cells].

Parameters of degradation of p-toluenesulfonate (TS) by free and agar-embedded Comamonas testosteroni BS1310 (pBS1010) cells were determined. The maximum rate of TS degradation was 25% lower in by immobilized than free cells, equaling 11 nmol x min(-1) x mg(-1) cells. Degradation of TS by both free and immobilized cells was associated with molecular oxygen consumption (molar ratio, 1 : 2). In a plug-flow reactor, the degradation rate was 10.4 nmol x min(-1) x mg(-1) cells. The results can be applied to designing reactors for TS degradation in sewage and developing biosensors.

Agar↗
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[Use of NMR spectroscopy in studies of sorbitol and glucose transformation by Gluconobacter oxydans].

NMR spectroscopy was applied for studying the products of glucose and sorbitol oxidation by cells of Gluconobacter oxydans. An analysis of 1H NMR spectra showed that the transformation of glucose results in the formation of diketogluconic acid, and sorbitol is oxidized to sorbose. In the 32P NMR spectra, only a signal of inorganic phosphate was detected, which accumulated in the medium as a result of cell lysis.

Biotransformation↗
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[Myocardial parameters controlling vulnerability. Analysis of mathematical models].

Vulnerability induced by application of a properly timed premature stimulus was studied on mathematical models. Two mechanisms of vulnerability 1) reentry, 2) focal reexcitation were analysed. Tissue with a region of increased refractory period Rmax was simulated on Wiener's type model. The influence of high refractoriness region dimensions and tissue parameters on the duration of vulnarable period was studied. Reentry was shown to appear on the border of high refractoriness region, which minimal length lmin being the shorter, the greater was tau (maximal latency of response) and epsilon (epsilon = deltaR/R--degree of heterogeneity). The dependence of vulnerable period duration on current strength was computed for Nobel's model. The dip-phenomenon was found in this model, the vulnerable zone was located above the minimal value of threshold.

Animals↗
PubMedDate not supplied

[Biosensor models based on potentiometric and amperometric transducers for use in medicine, biotechnology, and environmental monitoring (review)].

Various types of potentiometric and amperometric biosensors are characterized: microbial sensors with Gluconobacter oxydans cells with potentiometric (pH-sensitive field-effect transistor) and amperometric (Clark-type) electrodes for determining glucose; a potentiometric enzymatic electrode with butyrylcholinesterase, which is used in the biosensor designed to detect pesticides; immunosensors with pH-sensitive field-effect transistors which detect the herbicide 2, 4-D; a biosensor for human immunoglobulin G; biosensors with anaerobic bacteria Clostridium thermocellum; chemical and enzymatic sensors containing a photosensitive membrane for determining ammonium ions and urea; and amperometric microbial sensors prepared with Pseudomonas cells for determining naphthalene, biphenyl, and polychlorinated benzoates. Practical applications of the developed models of biosensors to medicine, biotechnology, and environmental monitoring are discussed.

Biosensing Techniques↗
PubMedDate not supplied

[Sensor for rapid measurement of blood glucose].

Bacterial biosensor consisting of Gluconobacter oxydans cells immobilized on the surface of oxygen electrode was used for measuring glucose concentration in human blood serum. The results were compared with those of standard clinical method (color reaction with ortho-toluidine). The proposed biosensor permits highly accurate measurements (mean quadratic deviation no more than 2% of the mean arithmetic), the coefficient of correlation with the results of standard method being 0.970.

Acetobacteraceae↗