Submerged cultivation of Stephania glabra (Roxb.) Miers cells in different systems: Specific features of growth and accumulation of alkaloid stepharine

Strains of a Stephania glabra suspension culture grown in flasks and two types of bioreactors (laboratory-scale bubble and pilot-scale stirred reactors) have been compared according to their growth characteristics and accumulation of the alkaloid stepharine. The best characteristics have been recorded for strains 113 and 261. In the case of batch cultivation in flasks, the maximal accumulation of dry biomass by these strains reaches 19–21 g/l; that of the alkaloid stepharine, 0.30–0.35% of dry biomass. The used strains differ in their response to cultivation scale-up from flasks to bioreactors, strain 254 displaying the lowest adaptation to such changes. A bubble reactor is the most beneficial system for submerged cultivation of S. glabra. The absence of detectable stepharine synthesis on the background of a considerable decrease in all growth characteristics of the cultures has been observed when using a pilot stirred bioreactor. The batch cultures of strains 113 and 261 in a bubble bioreactor accumulate 11–16 g/l of dry biomass containing 0.05–0.16% of the alkaloid. It has been shown that strains 113 and 261 retain satisfactory physiological characteristics in a semi-flow regime of a bubble bioreactor. This scale-up scheme can be used for further industrial cultivation.     

Epidemiologic situation and measures for prevention of infectious diseases in Sverdlovsk region in 2006-2007

Materials characterizing the epidemiologic situation on most significant infectious diseases in Sverdlovsk region are presented. Experience on providing the epidemiologic welfare based on systematic surveillance for activity of various factors influencing the epidemic process is described.     

Investigation of systemic control of plant cell division and differentiation in the model of tumor growth in radish

The study addresses the control of plant cell division and differentiation using the model of tumor-forming lines of radish. Expression of the genes involved in control of the cell cycle (CycD3), maintenance of meristematic cell activity (STM, WUS, and KNAT1), and primary response to cytokinin (ARR) was studied in inbred radish lines characterized by tumor growth at different stages of development. The influence of exogenic cytokinin on the expression of the genes of interest is analyzed. The possible role of the CycD3, KNAT1, tSTM, WUS, and ARR5 in tumor formation in radish is discussed.     

Mapping of quantitative trait loci (QTL) associated with activity of disulfide reductase and lipoxygenase in grain of bread wheat <Emphasis Type="Italic">Triticum aestivum</Emphasis> L.

Activity of two enzymes of thiol-disulfide cell metabolism, lipoxygenase (LOX, EC 1.13.11.12) and disulfide-reductase (TPDO, EC 1.8.4.2) was studied in recombinant inbred lines of bread wheat ITMI. Their activity in the caryopsis may be connected with the gluten quality, one of the most important traits significant for breeding. The activity of lipoxygenase under favorable and droughty environmental conditions was shown to be associated with the quantitative trait locus (QTL) located on chromosome 4BS near the structural gene of a subunit of this enzyme. However, no QTL common to this enzyme and any characteristic of gluten quality have been found. Four loci responsible for the activity of disulfide reductase were identified on chromosomes 4A, 5D, 6A, and 7D. Previously, indicators of grain and flour properties, such as elasticity, flour strenght, and grain hardiness were mapped at the same loci. This indicates that the given enzyme participates in the formation of the protein complex upon maturation of wheat grain. The detected QTL can be involved in further genetic studies designed to establish the regularities of gluten formation.     

Gamma Power Is Phase-Locked to Posterior Alpha Activity

Neuronal oscillations in various frequency bands have been reported in numerous studies in both humans and animals. While it is obvious that these oscillations play an important role in cognitive processing, it remains unclear how oscillations in various frequency bands interact. In this study we have investigated phase to power locking in MEG activity of healthy human subjects at rest with their eyes closed. To examine cross-frequency coupling, we have computed coherence between the time course of the power in a given frequency band and the signal itself within every channel. The time-course of the power was calculated using a sliding tapered time window followed by a Fourier transform. Our findings show that high-frequency gamma power (30–70 Hz) is phase-locked to alpha oscillations (8–13 Hz) in the ongoing MEG signals. The topography of the coupling was similar to the topography of the alpha power and was strongest over occipital areas. Interestingly, gamma activity per se was not evident in the power spectra and only became detectable when studied in relation to the alpha phase. Intracranial data from an epileptic subject confirmed these findings albeit there was slowing in both the alpha and gamma band. A tentative explanation for this phenomenon is that the visual system is inhibited during most of the alpha cycle whereas a burst of gamma activity at a specific alpha phase (e.g. at troughs) reflects a window of excitability.     

Freezing Resistance and Cryopreservation of Cell Strains of Rhaponticum carthamoides and Thalictrum minus

Effects of long-term (few months) culturing and short pregrowth (up to 7 days prior to deep freezing) in the presence of mannitol (5–6%), ABA (5.0–7.5 × 10^–5 M), or both substances on cryogenic resistance of leusea (Rhaponticum carthamoides, strains Rhs-2 and Rhs-8) and meadow rue (Thalictrum minus L., strain B-233) cell suspension cultures were studied. Cryoprotective capacities of 48 solutions were studied at slow (0.33°C/min) freezing to the temperature of liquid nitrogen with an automatic initiation of crystallization. Cells were stored in liquid nitrogen for several days or months. ABA had a cryoprotective effect, provided that subculturing intervals were 12–14 days. At more frequent subculturing (every 7 days), pregrowth on ABA-containing medium did not increase survival percentage compared to pregrowth with mannitol. Successful cryopreservation of these strains has been achieved due to strict standardization of 7-day subculturing regime, pregrowth in the presence of mannitol prior to freezing, and cryopreservation with dimethyl sulfoxide, sucrose, trehalose, and glycerol. The cell survival rates after thawing were 60% (Rhs-8), 80% (Rhs-2), and 70% (B-233). The cell growth resumed on the third to seventh day. The growth indices and protoberberine synthesizing activity in B-233 strain reached their control values at the ninth subculturing after a post-thaw recovery.     

The central Siberian origin for native American Y chromosomes.

Y chromosomal DNA polymorphisms were used to investigate Pleistocene male migrations to the American continent. In a worldwide sample of 306 men, we obtained 32 haplotypes constructed with the variation found in 30 distinct polymorphic sites. The major Y haplotype present in most Native Americans was traced back to recent ancestors common with Siberians, namely, the Kets and Altaians from the Yenissey River Basin and Altai Mountains, respectively. Going further back, the next common ancestor gave rise also to Caucasoid Y chromosomes, probably from the central Eurasian region. This study, therefore, suggests a predominantly central Siberian origin for Native American paternal lineages for those who could have migrated to the Americas during the Upper Pleistocene.     

The role of histone H2B from sea urchin sperm in the association of reconstituted minichromosomes

A comparative study of the condensation of reconstituted complexes of circular SV40 DNA with core histones from calf thymus and sea urchin sperm was performed using sedimentation and electron microscopic techniques. It is shown that in low ionic strength solutions both types of complexes are similar to native minichromosomes. In the region from 0.08 to 0.16 M NaCl the complexes of SV40 DNA with thymus histones form small compact particles. By contrast, the compaction of the SV40 DNA complexes with sperm histones results in the formation of giant intermolecular associates. The results obtained may mean that histone H2B of sea urchin sperm participates in the formation of a higher order structure in sperm chromatin.     

Reindeer Chukchi and Siberian Eskimos: Studies on blood groups,serum proteins,and red cell enzymes with regard to genetic heterogeneity

Phenotype and allelic frequencies for ABO, MNSs, P, Rh, Kell, Duffy, and Diego blood groups, as well as for transferrins (Tf), haptoglobins (Hp), phosphoglucomutase 1 (PGM₁), adenylate kinase (AK), 6-phosphogluconate dehydrogenase (PGD), and acid phosphatase (AcP) are described in 9–10 adjoining populations of Reindeer Chukchi. Additionally, one of three presently existing territorial subgroups of Siberian Eskimos was studied. The total sample size ranges from 931 to 1,066 in Chukchi, and from 99 to 102 in Eskimos, depending on the genetic system studied. Substantially reduced samples for Kidd and ABO secretion were investigated solely in the Reindeer Chukchi. Significant heterogeneity of allelic frequencies has been observed among Chukchi populations (χ = 378.47, P < 0.001). Summed genetic heterogeneity between Reindeer Chukchi and Siberian Eskimos was also found to be highly significant (χ = 186.54, P < 0.001). Both groups can be readily discriminated with only four outliers: NS , P¹, R¹, and P^a. Random genetic drift is suggested to be responsible for a large proportion of heterogeneity of allelic frequencies at the MNSs, P, and Rh blood-group system sites both among the Chukchi and Eskimos. Conversely, stabilizing selection is assumed as the principal agent maintaining homogeneous allelic frequencies at the AcP locus within the Chukchi subdivisions, whereas disruptive selection may be considered as a major factor leading to different p^a frequencies between Chukchi and Eskimos.