A comparative study of delayed hypersensitivity due to mycobacteria and their isolated protein fractions

The role of intracellular protein fractions, isolated from M. tuberculosis virulent strains in the process of the electrophoretic separation, in the development of delayed hypersensitivity reactions has been studied. Low reactogenicity of protein fractions has been established on the basis of the development of faint immunopathological reactions in sensitized animals. High-molecular fraction 1 may be used as a sensitive preparation for the differentiation of individual mycobacterial species.     

The geographic ranges of Martes species (Carnivora,Mustelidae) in the Middle Urals in the Late Pleistocene and Holocene

Martes mandibles from Late Pleistocene and Holocene sites in the Middle Urals were identified to the species level using discriminant analysis. As has been shown, sable lived there in the Late Pleistocene, with its geographic range covering all this area until the end of the 18th century; however, its range started to reduce towards the north and northeast in the early 19th century. Over 150 years, the southwestern boundary of the sable range shifted by 3° to reach the current position by the mid-20th century. The pine marten appeared in the Middle Urals in the Holocene no later than 8000 years ago and inhabits this territory at present.     

Biochemical evaluation of the morphogenetic potential of wheat callus cells in vitro

Morphogenetic processes in immature embryos of wheat (Triticum aestivum L.) were investigated using a molecular marker for meristematic cells of cereals (proliferative antigen of meristem initial cells, PAIC). The used genetic model comprised a series of almost isogenic lines of wheat alternative by the alleles of dwarfing genes (RhtB1c, RhtB1b, and Rht14) and the original cv. Saratovskaya 29. The Rht genetic system was found to affect the level of PAIC in the wheat callus cells during callus formation and subsequent regeneration. We found differences in the level of PAIC at certain stages of culturing and a general trend of its content in the course of callus formation and secondary differentiation in the callus tissue. Possible role of PAIC as a marker of meristematic centers within the callus tissue and the prospect of its use in breeding as an additional criterion for estimation of morphogenetic ability of the newly produced lines of wheat are discussed.     

Air-directed attachment of coccoid bacteria to the surface of superhydrophobic lotus-like titanium

Superhydrophobic titanium surfaces fabricated by femtosecond laser ablation to mimic the structure of lotus leaves were assessed for their ability to retain coccoid bacteria. Staphylococcus aureus CIP 65.8T, S. aureus ATCC 25923, S. epidermidis ATCC 14990T and Planococcus maritimus KMM 3738 were retained by the surface, to varying degrees. However, each strain was found to preferentially attach to the crevices located between the microscale surface features. The upper regions of the microscale features remained essentially cell-free. It was hypothesised that air entrapped by the topographical features inhibited contact between the cells and the titanium substratum. Synchrotron SAXS revealed that even after immersion for 50 min, nano-sized air bubbles covered 45% of the titanium surface. After 1 h the number of cells of S. aureus CIP 65.8T attached to the lotus-like titanium increased to 1.27×10(5) mm(-2), coinciding with the replacement of trapped air by the incubation medium.     

Prostate cancer PET bioprobes: synthesis of [18F]-radiolabeled hydroxyflutamide derivatives

Approximately 80-90% of prostate cancers are androgen dependent at initial diagnosis. The androgen receptor (AR) is present in most advanced prostate cancer specimens and is believed to have a critical role in its development. Today, treatment of prostate cancer is done by inhibition of AR using antiandrogens such as flutamide (pro-drug of hydroxyflutamide), nilutamide, and bicalutamide. However, there is currently no noninvasive imaging modalities to detect, guide, and monitor specific treatment of AR-positive prostate cancer. (R)-3-Bromo-N-(4-fluoro-3-(trifluoromethyl)phenyl)-2-hydroxy-2-methyl-propanamide [18F]-1 and N-(4-fluoro-3-(trifluoromethyl)phenyl)-2-hydroxy-2-methylpropanamide [18F]-2, derivatives of hydroxyflutamide, were synthesized as a fluorine-containing imaging agent candidates. A three-step fluorine-18 radiosynthesis route was developed, and the compounds were successfully labeled with a 10+/-3% decay corrected radiochemical yield, 95% radiochemical purity, and a specific activity of 1500+/-200 Ci/mmol end of bombardment (n = 10). These labeled biprobes not only may enable for the future quantitative molecular imaging of AR-positive prostate cancer using positron emission tomography but may also allow for image-guided treatment of prostate cancer.     

Cytogenetic effects of low doses of radiation in mammalian cells: analysis of the hypersensitivity phenomenon and induced resistance

The induction of cytogenetic damage after irradiation of chinese hamster cells and human melanoma cells within a dose range 1-200 cGy was studied. The anaphase and metaphase analysis of chromosome damage and micronuclei test were applied. The hypersensitivity (HRS) at doses below 20 cGy and the increased radio-resistence at higher doses (IR) were shown with all cytogenetic critheria for both cell lines. The phenomenon of HRS/IR was reproduced in synchronic as well as in a synchronic population of chinese hamster cells. This fact shows that HRS was caused by high radiosensitivity of all cells and can not be explained by any differential sensitivity of cells in different phase of the cell cycle. So it was supposed that the increasing radio-resistence is determined by the inclusion of the inducible repair processes in all cells. This conclusion consents with the facts, that there was no evidence of HRS on dose-effect curves and that some parts of pre-existent damage was repaired after preliminary irradiation with low doses (1-20 cGy) which induce repair processes. It can be concluded that same inducible repair processes an analogous in mechanisms underlying in the base of HRS/IR phenomenon and adaptive response.     

Synchronous genetic turnovers across Western Eurasia in Late Pleistocene collared lemmings

Recent palaeogenetic studies indicate a highly dynamic history in collared lemmings (Dicrostonyx spp.), with several demographical changes linked to climatic fluctuations that took place during the last glaciation. At the western range margin of D. torquatus, these changes were characterized by a series of local extinctions and recolonizations. However, it is unclear whether this pattern represents a local phenomenon, possibly driven by ecological edge effects, or a global phenomenon that took place across large geographical scales. To address this, we explored the palaeogenetic history of the collared lemming using a next‐generation sequencing approach for pooled mitochondrial DNA amplicons. Sequences were obtained from over 300 fossil remains sampled across Eurasia and two sites in North America. We identified five mitochondrial lineages of D. torquatus that succeeded each other through time across Europe and western Russia, indicating a history of repeated population extinctions and recolonizations, most likely from eastern Russia, during the last 50 000 years. The observation of repeated extinctions across such a vast geographical range indicates large‐scale changes in the steppe‐tundra environment in western Eurasia during the last glaciation. All Holocene samples, from across the species' entire range, belonged to only one of the five mitochondrial lineages. Thus, extant D. torquatus populations only harbour a small fraction of the total genetic diversity that existed across different stages of the Late Pleistocene. In North American samples, haplotypes belonging to both D. groenlandicus and D. richardsoni were recovered from a Late Pleistocene site in south‐western Canada. This suggests that D. groenlandicus had a more southern and D. richardsoni a more northern glacial distribution than previously thought. This study provides significant insights into the population dynamics of a small mammal at a large geographical scale and reveals a rather complex demographical history, which could have had bottom‐up effects in the Late Pleistocene steppe‐tundra ecosystem.     

Genetic characterization of toxigenic Vibrio cholerae non-O1/non-O139 strains, isolated in the Middle Asia

Here, we report on the characterization of 22 clinical toxigenic V. cholerae non-O1/non-O139 strains isolated in the Middle Asia (Uzbekistan) in 1971–1990. PCR analysis has revealed that these strains contain the main virulence genes such as ctxA, zot, ace (CTXφ); rstC (RS1φ); tcpA, toxT, aldA (pathogenicity island VPI), but they lack both pandemic islands VSP-I and VSP-II specific to epidemic strains of O1 serogroup of El Tor biotype and O139 serogroup. Only two of the twenty two toxigenic strains have tcpA gene of El Tor type, one strain has tcpA gene of classical type, while nineteen other strains carry a new variant of this gene, designated as tcpA ^uzb. Nucleotide sequences analysis of virulence genes in toxigenic V. cholerae non-O1/non-O139 strains from Uzbekistan showed that they differ significantly from the sequences of these genes in epidemic O1 and O139 strain indicating that they belong to a separate line of evolution of virulent V. cholerae strains. For the first time it is shown that V. cholerae non-O1/non-O139 toxigenic strains of different serogroups may belong to the same clone.     

The role of recipient cells in the mechanism of pathological calcification of heart valve transplants

It was found using the model of subcutaneous implantation in rats that the calcification of the aorta wall occurs by two mechanisms of which one is dependent on, and the other independent of the migration of recipient cells to the transplant.