Various physico-chemical properties of the amylolytic complex from Bacillus mesentericus]

Some physico-chemical properties of the Bacillus mesentericus amylolytic complex were studied, and optimal conditions of starch hydrolysis (pH 7.5-8.0; 45 degrees C) were found. The half-life of amylases at 50 degrees was 75 min. The heat stability of the enzymes increased in the presence of Ca2+ ions. Amylase was stable at pH 7-9 and readily inactivated at pH below 6.0. By physical and chemical characteristics the complex was close to analogous preparations from Bacillus alkalophilic strains. Isoelectrofocusing revealed that the complex consisted at least of two amylolytic enzymes.     

A comparative analysis of the proteins from a cell culture and from field plants of the ecdysteroid producer Serratula coronata L.]

Differences in the composition and amount of proteins synthesized in the cell culture and leaves of field plants Serratula coronata have been shown. They proceed from differences in intensity of synthesis of secondary metabolites, ecdysteroids, whose content in the cell culture is considerably lower.     

DNA structural features on borders of ERBB2 amplicons in breast cancer

In 25–30% of cases of breast cancer tumors, the amplification of the chromosome fragment around ERBB2 underlies the increased expression of genes adjacent to ERBB2. The increased expression of genes within ERBB2-containing amplicons may impact not only the growth and development of the tumor, but also the sensitivity of the tumor to different types of anti-cancer therapies. The initial cause of the amplification and the exact borders of ERBB2-amplified chromosome fragment are still not completely characterized. No specific DNA sequences were found on the junction regions during intrachromosomal DNA amplification. We hypothesized that amplification borders can be specified by the structural peculiarities of DNA, rather than the particular DNA sequence. This study focused on the mapping of ERBB2 amplification borders in breast cancer and the search for unusual structural features of DNA at the borders of the identified amplicons. The copy number of ten genes adjacent to ERBB2 was evaluated by real time PCR in 162 breast cancer samples. Several ERBB2-containing amplicons of various lengths were revealed. In the majority of the analyzed samples, the borders of these amplicons were located within ZNFN1A3 and RARA genes. A bioinformatics analysis of the nucleotide sequence peculiarities around ERBB2 gene revealed the presence of AT-rich DNA regions with a high degree of flexibility. These regions were able to form stable secondary structures. Positions of these sites strongly coincide with the positions of the ERBB2-containing amplicon borders found in real time PCR experiments. Based on the obtained results, one can suppose that the structural features of DNA are involved in the formation of ERBB2-containing amplicon borders in breast cancer cells and the data are of importance for understanding the mechanisms of oncogene amplification.     

Catalytic properties of lipase adsorbed on nanocarbon-containing mesoporous silica in esterification and transesterification reactions

Nanocarbon-containing mesoporous silica covered with a varying amounts of nanostructured carbon of different morphologies were used as supports to immobilize Thermomyces lanuginosus lipase. The catalytic properties of the prepared biocatalysts were studied in both the transesterification of vegetable (linseed) oil in the presence of ethyl acetate and the esterification of the fatty acid (capric C10:0) in the presence of secondary (isopropyl or isoamyl) alcohols. The physico-chemical characteristics, such as the amount of adsorbed lipase, its specific activity, and the dependence of the activity and stability of the prepared biocatalysts on the support type were evaluated. The Michaelis-Menten kinetics was studied in the esterification of capric acid with isoamyl alcohol. The prepared biocatalysts were shown to retain up to 90% activity for >1000 h in the synthesis of isoamyl caprate. The half-time of the biocatalysts inactivation in the transesterification of linseed oil was found to be more than 700 h at 40°C.     

Investigation of Whalebone from the Miocene Kovran Locality (Kamchatka Krai,Russia)

New information on the microstructures, general morphology, and features of preservation of plates of a whalebone from the Miocene Kovran locality in the Kamchatka Peninsula are provided. The plates have a chevron-like bend which is absent in extant Balaenopteridae, Balaenidae, and Eschrichtiidae. This shape is possibly related to the filtration mechanism characteristic of these whales.     

A novel nucleic acid-binding protein that interacts with human rad51 recombinase.

Using the yeast two-hybrid system, we isolated a cDNA encoding a novel human protein, named Pir51, that strongly interacts with human Rad51 recombinase. Analysis in vitro confirmed the interaction between Rad51 and Pir51. Pir51 mRNA is expressed in a number of human organs, most notably in testis, thymus, colon and small intestine. The Pir51 gene locus was mapped to chromosome 12p13.1-13. 2 by fluorescence in situ hybridization. The Pir51 protein was expressed in Escherichia coli and purified to near homogeneity. Biochemical analysis shows that the Pir51 protein binds both single- and double-stranded DNA, and is capable of aggregating DNA. The protein also binds RNA. The Pir51 protein may represent a new member of the multiprotein complexes postulated to carry out homologous recombination and DNA repair in mammalian cells.     

Prevalence of mutations BRCA1 5382insC, and CHEK2 1100delC in the population of Siberian region

Frequencies of the 538insC mutation in the BRCA1 gene and the 1100delC mutation in the CHEK2 gene were compared in the group of breast cancer patients and the large-scale sample, consisting of 7920 DNA specimens from healthy residents of the city of Novosibirsk. Higher frequencies of these mutations in the patient group compared to the control sample (1.95 versus 0.25% for BRCA1 5382insC, and 1.78 versus 0.40% for CHEK2 1100delC) were observed, pointing to their association with susceptibility to breast cancer (OR = = 7.86, 95% CI 3.51-17.30 and OR =4.46, 95% C1 2.04-9.49, respectively).