Evaluation of a new assay for nontuberculous mycobacteria species identification in diagnostic material and cultures.

The purpose of the present study was to evaluate a real-time PCR system for 12 nontuberculous mycobacteria (NTM) species identification developed by Central Tuberculosis Research Institute (CTRI; Moscow, Russia) in cooperation with Syntol LLC (Moscow, Russia). NTM cultures (210 strains, 19 species), Mycobacterium tuberculosis complex (MTBC) cultures (21 strains, 2 species), non-mycobacterial microorganisms (18 strains, 13 species) were used for the first stage of the assay evaluation. Clinical samples (sputum, N = 973) positive for smear microscopy and MTBC/NTM DNA by a PCR-based screening assay collected from 819 patients were used for specificity and sensitivity evaluation.

New assay to diagnose and differentiate between Mycobacterium tuberculosis complex and nontuberculous mycobacteria.

The purpose of the present study was to create a real-time PCR test system allowing simultaneous detection of nontuberculous mycobacteria (NTM) and Mycobacterium tuberculosis complex (MTBC) both in culture and sputum. NTM cultures (18 strains, 18 species), MTBC cultures (16 strains, 2 species) and non-mycobacterial microorganisms from the collection of the Central Research TB Institute (CTRI) were used for the preliminary evaluation of the test system. 301 NTM cultures from patients with mycobacteriosis were used to assess the sensitivity of the developed test system.

Mathematical model of polymerase chain reaction with temperature-dependent parameters.

The course of the real-time polymerase chain reaction (PCR) is determined by the temperature dependence of the kinetics of the component reactions, particularly the DNA strand hybridization. To investigate the effect of thermal processes on the reaction behavior, a mathematical model in which the variable rate constant of dissociation of "primer-single strand" complexes depends on temperature was proposed. The reaction medium temperature, which depends on time, was also introduced into the model.

Alternative solution of the simplest model of enzymatic synthesis of nucleic acids by homotopy perturbation method.

Development of methods for obtaining approximate analytical solutions of nonlinear differential equations and their systems is a rapidly developing field of mathematical physics. Earlier, an approximate solution of the simplest system of kinetic enzymatic equations for calculating dynamics of complementary strands of nucleic acids was obtained. In this study, we consider an alternative approach to selecting the basic linear approximation of the used method, which makes it possible to obtain more accurate analytical solutions of the set problem.

Approximate analytic solution of a simple system of kinetic equations describing the enzymatic synthesis of nucleic acids.

Macroscopic kinetic models describing the process of polymerase chain reaction (PCR) are currently solved only by numerical methods, which hampers the development of effective software algorithms for processing the results of the reaction. This paper considers the application of the homotopy perturbation method for obtaining approximate analytical solution of the simplest system of enzymatic kinetic equations describing the synthesis of nucleic acid molecules during PCR. The resulting approximate analytic solution with high accuracy reproduces the results of a numerical solution of the system in a wide range of ratios of enzyme and substrate concentrations both for the case of a large excess of the substrate over the enzyme and vice versa.