[Malignancy monitoring in the pediatric population of the Orenburg Region].

The paper gives the results of a retrospective epidemiological survey for malignances in the pediatric population of the Orenburg Region in 1995 to 2007. The average long-term morbidity rates were determined by the main (central, western, eastern) areas of the region; the areas were ranked by the malignancy morbidity rates among the pediatric population as a whole and by nosological entities. The authors provide the structural characteristics of cancer in the Orenburg Region as compared with the general Russian data.

Transgene-induced silencing identifies sequences involved in the establishment of paramutation of the maize p1 gene.

A transgene carrying a distal enhancer element of the maize P1-rr promoter caused silencing of an endogenous P1-rr allele in the progeny of transgenic maize plants. Expression of both the transgene and the endogenous P1-rr allele was reduced in the affected plants. The silenced phenotype was observed in the progeny of seven of eight crosses involving three independent transgenic events tested (average frequency of 19%). This phenotype was associated with an induced epigenetic state of the P1-rr allele, termed P1-rr', which is characterized by increased methylation of the P1-rr flanking regions and decreased levels of P1-rr transcript. The P1-rr' epiallele is highly heritable in the absence of the inducing P1.2b::GUS transgene, and it can impose an equivalent state on a naive P1-rr allele in subsequent crosses (paramutation). In contrast, parallel experiments with two other P::GUS transgenes that contained the same basal P1-rr promoter fragment but different upstream sequences revealed no detectable silencing effect. Thus, transgenes carrying a specific enhancer fragment of the P1-rr gene promoter can trigger a paramutant state (P1-rr') of the endogenous P1-rr gene that is maintained in the absence of the inducing transgene. We discuss the potential role of the P1-rr distal enhancer element in the establishment and propagation of a paramutation system in maize.

Hierarchical patterns of transgene expression indicate involvement of developmental mechanisms in the regulation of the maize P1-rr promoter.

The maize P1-rr gene encodes a Myb-homologous transcription factor that regulates the synthesis of red flavonoid pigments. Maize plants transformed with segments of the P1-rr promoter driving a GUS reporter gene exhibit significant variation in transgene expression, both between independent transformation events and among sibling plants derived from a single event. Interestingly, variability in spatial expression is not random; rather, transgene activity occurs predominantly in five patterns that fit a hierarchy: expression is most common in kernel pericarp, with sequential addition of expression in cob glumes, husk, silk, and tassel. The hierarchical expression pattern of P-rr::GUS transgenes suggests a possible model for developmental regulation of the P1-rr gene. Our results demonstrate that variability in transgene expression, a common occurrence in transgenic plant studies, can be informative if adequately analyzed to uncover underlying patterns of gene expression.

Complex structure of a maize Myb gene promoter: functional analysis in transgenic plants.

The maize P gene encodes a Myb-like transcription factor that regulates synthesis of red flavonoid pigments in floral organs. To study the transcriptional regulation of the P gene, candidate regulatory sequences of the P1-rr gene promoter were identified by Ac insertional mutagenesis and subjected to functional testing in transgenic maize plants. The results indicate that a 561 bp fragment (Pb) encompassing the transcription start site (-235 to +326) supports weak expression of a GUS reporter gene in floral organs, including husk, silk, kernel pericarp, cob and male inflorescence. Two other fragments, located approximately 1 and 5 kb 5' of the transcription start site, increased the levels of GUS activity in floral tissues and thus appear to contain enhancer elements. All of the tested constructs gave similar patterns of GUS expression, suggesting that the 561 bp Pb fragment that is common among the transgene constructs contains regulatory elements that promote activation in floral organs. The basal promoter and proximal enhancer fragments contain putative binding sites for bZip regulatory factors, and a complex arrangement of palindromes including a large inverted repeat of two tRNA-like genes. Possibly, interconversions between linear and cruciform conformations of the palindromes may affect protein/DNA interactions and thereby modulate P1-rr expression.

[Determination of adenine nucleotide and inorganic phosphate contents of liver of rats with E-hypovitaminosis and administration of alpha-tocopherol and ubiquinone-9]. / Opredelenie soderzhaniia adeninnukleotidov i neorganicheskogo fosfata v pecheni krys pri E-gipovitaminoze i vvedenii al'fa-tokoferola i ubikhinoma-9.

It is shown that in the rat liver with E-hypovitaminosis the ATP content, sum of adenine nucleotides, and the phosphate potential value ([ATP]/[ADP.]Pi) decrease, whereas the amount of ADP, AMP and Pi remains practically unchanged. 3h after intravenous administration of alpha-tocopherol of ubiquinone to rats with E-hyovitaminosis the mentioned indices normalize, which evidences for a considerable increase in the level of bioenergetic processes. The direction of the mentioned changes corresponds to changes in the ubiquinone content and activity of the respiratory chain redox enzymes. The participation of vitamin E in processes of oxidative phosphorylation may be connected with the metabolism control and ubiquinone functioning.