[Transformation of amides by adherent rhodococcus cells possessing amidase activity].

We report the development of a heterogeneous biocatalyst for the hydrolysis of amides that is based on cell adhesion ofamidase-containing Rhodococci on activated birch carbon (ABC) and crude carbon. We investigated the properties of the obtained biocatalyst in the hydrolysis reaction of acrylamide to acrylic acid and nicotinamide to nicotinic acid, as well as in a model reaction of racemic lactamide hydrolysis to a mixture of D- and L-isomers of lactic acid. We show that a six- and threefold increase in the concentrations of adherent and suspended cells, respectively, results in a reduction of amidase activity by 3 and 30 times, respectively. ABC Cells adherent on ABC maintained more than 50% of enzymatic activity for seven 24-hour cycles of acrylamide hydrolysis, while suspended cells lost more than 60% of activity already in the second cycle. We also noted that cell adhesion on ABC reduced the stereoselectivity of hydrolysis reaction of racemic lactamide.

[The relationship between EGFR mutation and clinico-pathological features of lung adenocarcinoma in residents of southern Russia].

The study was designed to analyse the relationship between EGFR mutation and clinico-pathological features of lung adenocarcinoma in residents of southern Russia taking account oftheir age and sex, localization of the primary tumour, its cell differentiation, regional metastases, stage of disease and smoking status of the patients with mutant and wild-type EGFR genes. The frequency analysis included 29 somatic mutations in EGFR exones 18-21. The study revealed statistically significant associations of EGFR gene mutations with gender, smoking and stage of disease.

[Transformation of 2- and 4-cyanopyridines by free and immobilized cells of nitrile-hydrolyzing bacteria].

The transformation dynamics of 2- and 4-cyanopyridines by cells suspended and adsorbed on inorganic carriers has been studied in the Rhodococcus ruber gt 1 strain possessing nitrile hydratase activity and the Pseudomonas fluorescens C2 strain containing nitrilase. It was shown that both nitrile hydratase and nitrilase activities of immobilized cells against 2-cyanopyridine were 1.5-4 times lower compared to 4-cyanopyridine and 1.6-2 times lower than the activities of free cells against 2-cyanpopyridine. The possibility of obtaining isonicotinic acid during the combined conversion of 4-cyanopyridine by a mixed suspension of R. ruber gt 1 cells with a high level of nitrile hydratase activity and R. erythropolis 11-2 cells with a pronounced activity of amidase has been shown. Immobilization of Rhodococcus cells on raw coal and Pseudomonas cells on china clay was shown to yield a heterogeneous biocatalyst for the efficient transformation of cyanopyridines into respective amides and carbonic acids.

[Catalytic properties of a nitrile hydratase immobilized on activated chitosan].

The catalytic properties of a nitrile hydratase, isolated from a strain of Rhodococcus ruber gt1 and immobilized by covalent cross-linking with chitosan activated with 0.1% benzoquinone solution, have been investigated. The kinetic parameters ofacrylonitrile hydration catalyzed by immobilized nitrile hydratase and the enzyme in a solution have been determined. It is found that the immobilization does not lead to a decrease in the maximum reaction rate (Vmax), whereas the Michaelis constant (K(M)) is reduced by a factor of 2.4. The possibility of reusing an immobilized enzyme for 50 consecutive cycles of acrylonitrile transformation was shown, and the nitrile hydratase activity in the 50th cycle exceeded that in the first cycle by 3.5 times. It is shown that the effect of temperature on activity depended on the concentration of the enzyme, which confirms the dissociative nature of nitrile hydratase inactivation. It was found that immobilized nitrile hydratases remain active at pH 3.0-4.0, whereas the enzyme is inactivated in a solution under these conditions. The resulting biocatalyst can be effectively used to receive acrylamide from acrylonitrile.

[A study of the catalytic properties of the nitrile hydratase immobilized on aluminum oxides and carbon-containing adsorbents].

The nitrile hydratase isolated from Rhodococcus ruber strain gt1, displaying a high nitrile hydratase activity, was immobilized on unmodified aluminum oxides and carbon-containing adsorbents, including the carbon carrier Sibunit. The activity and operational stability of the immobilized nitrile hydratase were studied in the reaction of acrylonitrile transformation into acrylamide. It was demonstrated that an increase in the carbon content in the carrier led to an increase in the amount of adsorbed enzyme and, concurrently, to a decrease in its activity. The nitrile hydratase immobilized on Sibunit and carbon-containing aluminum alpha-oxide having a "crust" structure displayed the highest operational stability in acrylonitrile hydration. It was shown that the thermostability of adsorbed nitrile hydratase increased by one order of magnitude.

[Emergence of the integron-positive multi-drug resistant strain of Acinetobacter baumanii in Russian hospitals].

AIM: To detect the integron-positive strains among nosocomial Acinetobacter spp. and to determine their relationship on the genotype level. MATERIALS AND METHODS: Amplification by polymerase chain reaction using primers specific to sequences of the class 1 and 2 intergrons on the genomic DNA template followed by restriction fragments length polymorphism analysis as well as RAPD-genotyping of the integron-positive strains were performed. RESULTS: Fact of spreading of Acinetobacter baumanii strain containing class 1 integron in medical centers was established. The composition of the integron's gene cassettes was analogous to worldwide (including epidemic) types. CONCLUSION: Molecular genetic analysis of the mobilized structures (integrons) under the standardization of used approaches are suitable for the surveillance for circulation of epidemic strains of nosocomial pathogens.

[Immobilization of Rhodococcus ruber strain gt1, possessing nitrile hydratase activity, on carbon sorbents].

Rhodococcus ruber strain gtl, possessing nitrile hydratase activity, was immobilized by adsorption on carbon supports differing in structure and porosity. The adsorption capacity of the supports towards cells, the substrate of the nitrile hydratase reaction (acrylonitrile), and the product (acrylamide) was studied. Also, the effect of immobilization and nitrile hydratase activity of bacteria was investigated, and the operational stability of the immobilized biocatalyst was determined. It was shown that crushed and granulated active coals were more appropriate for immobilization than fibrous carbon adsorbents.

[Genetic variety of Acinetobacter baumannii in an intensive care unit for burn patients].

The genetic structure of A. baumannii hospital isolates, formed in the course of 2002 - 2004 in an intensive care unit for burn patients (St. Petersburg) was studied. The prolonged circulation of only some clonal strains was shown, 35% of the isolates belonged to dominating strains. Phenotypically, all cultures were characterized by resistance to the preparations of the cephalosporin row and gentamicin. The presence of class 1 integron with variable segment sized 2.5 kbp was found in the genotype of four isolates with the use the polymerase chain reaction. The restriction analysis revealed its similarity with integron, detected earlier (in 1989 - 2001 ) in A. baumannii in European hospitals abroad.

[Integrons of bacteria isolated from aquatic environment].

Bacteria of the genus Pseudomonas, isolated from the water of the lakes Shira and Itkul (Republic of Khakassia, Russia) were shown to contain integrons of class 1 with gene cassettes, contained in the variable segment (sized 1 and 1.3 kb), were shown. Out of three detected integrons only one integron (in P. aeruginosa) included the sulfanilamide resistance gene contained in the 3'-conservative segment. The resistance of bacteria to kanamycin and ceftazidime was not seemingly linked with the presence of integrons. On the whole, the study revealed the presence of a significant proportion (27%) of integron-positive strains among aquatic bacteria with pronounced resistance to antibiotics.

[The effect of silver sulfadiazine on Acinetobacter baumannii strains isolated in burn units].

The genotype structure and silver sulfadiazine (SDS) resistance of a number of Acinetobacter baumanii strains that circulated for a prolonged period of time in burn UCUs were studied. The most resistant strain (SDS MIC 50 mcg/ml) contained a class 1 integron with the gene of sulfonamides resistance (sul1) in its genome. Possible reasons for selection of the multiple resistance among Acinetobacter spp. in burn units are discussed.

[PCR genotyping of Acinetobacter hospital isolates]. / PTSR-genotipirovanie gospital'nykh izoliatov Acinetobacter.

A total of 13 Acinetobacter baumannii-13TU isolates obtained from patients of the Perm regional clinical hospital during the period of 1 year, were genotyped in the polymerase chain reaction (PCR) with universal primers. Acinetobacter cultures could not be distinguished by phenotypic tests and antibiogram and were resistant to B-lactams and gentamicin. According to the results of amplification the obtained isolates could be subdivided into two groups (with 6 and 7 respectively). The detection of "epidemic" strains, including those capable of prolonged (for more than 5 months) persistence in hospital environment, may be indicative of the growing role of Acinetobacter as the causative agent in nosocomial infection.

[Effects of nitriles and amides on the growth and the nitrile hydratase activity of the Rhodococcus sp. strain gt1]. / Vliianie nitrilov i amidov na rost i nitrilgidrataznuiu aktivnost' shtamma Rhodococcus sp. gt1.

Effects of some nitriles and amides, as well as glucose and ammonium, on the growth and the nitrile hydratase (EC 4.2.1.84) activity of the Rhodococcus sp. strain gt1 isolated from soil were studied. The activity of nitrile hydratase mainly depended on carbon and nitrogen supply to cells. The activity of nitrile hydratase was high in the presence of glucose and ammonium at medium concentrations and decreased at concentrations of glucose more than 0.3%. Saturated unsubstituted aliphatic nitriles and amides were found to be a good source of nitrogen and carbon. However, the presence of nitriles and amides in the medium was not absolutely necessary for the expression of the activity of nitrile hydratase isolated from the Rhodococcus sp. strain gt1.