Efficiency of Transient Expression in Protoplasts of Various Potato Cultivars

Applied Biochemistry and Microbiology - The production of mesophilic protoplasts of potato (Solanum tuberosum L.) for transient gene expression is a required technological stage in the testing of...     

Combined Effect of Neutron and Proton Radiations on the Growth of Solid Ehrlich Ascites Carcinoma and Remote Effects in Mice

Doklady Biochemistry and Biophysics - The combined effect of the irradiation with a proton pencil scanning beam (PBS) at a total dose of 80 Gy and neutron radiation at a dose of 5 Gy on the growth...     

Structural and functional analysis of new plant promoter pro-SmAMP1 from <Emphasis Type="Italic">Stellaria media</Emphasis>

The nucleotide sequence of a fragment of the promoter region of pro-SmAMP1 gene, having a length of 1257 bp and encoding antifungal peptides, was determined in chickweed (Stellaria media (L.) Vill.). Computer analysis of the nucleotide sequence revealed a number of cis-elements that are typical strong plant promoters. Five 5′-deletion variants were created taking into account the distribution of cis-elements:–1235,–771,–714,–603, and–481 bp of pro-SmAMP1 gene promoter, which were fused to the coding region of the uidA reporter gene in pCambia1381Z plant expression vector. The efficacy of pro-SmAMP1 promoter deletion variants was determined by transient expression in plants of Nicotiana benthamiana and using sequential generations of transgenic Nicotiana tabacum plants. It was found that the levels of GUS reporter protein activity in the extracts from transgenic and agroinfiltrated plants using all deletion variants of pro-SmAMP1 gene promoter were 3–5 times higher than those of 35S CaMV viral promoter. The highest activity of GUS protein was observed in the leaves of transgenic tobacco plants and closely correlated with the mRNA level of encoding gene. The levels of GUS activity did not differ significantly among 11 independent homozygous lines of T₂ generation of N. tabacum plants with different deletion variants of pro-SmAMP1 promoter. The results give reason to assume that all deletion variants of pro-SmAMP1 promoter provide stable and high level of expression of controlled genes. The shortest deletion variant–481 bp of pro-SmAMP1 promoter should be viewed as a potentially strong plant promoter for the genetic engineering of plants.     

Mutilation of RNA phage Qbeta virus-like particles: from icosahedrons to rods

Icosahedral virus-like particles (VLPs) of RNA phage Qbeta are stabilized by four disulfide bonds of cysteine residues 74 and 80 within the loop between beta-strands F and G (FG loop) of the monomeric subunits, which determine the five-fold and quasi-six-fold symmetry contacts of the VLPs. In order to reduce the stability of Qbeta VLPs, we mutationally converted the amino acid stretch 76-ANGSCD-81 within the FG loop into the 76-VGGVEL-81 sequence. It led to production in Escherichia coli cells of aberrant rod-like Qbeta VLPs, along with normal icosahedral capsids. The length of the rod-like particles exceeded 4-30 times the diameter of icosahedral Qbeta VLPs.     

Digestive System of the Early Cretaceous Insect <Emphasis Type="Italic">Saurophthirus longipes</Emphasis> Ponomarenko (Insecta, ?Aphaniptera,Saurophthiroidea)

Information on the internal organization of Saurophthirus longipes Ponomarenko, 1976 from the Baissa locality in the western Transbaikalia is described and supplemented with the data on its digestive system. The entire intestine is straight, without bends or outgrowths. The proventriculus is hypertrophied and sclerotized; the midgut is wide, saclike; the hindgut is short, straight, undifferentiated probably due to pedomorphosis. Element analysis of the intestine content has not corroborated hematophagy with certainty. Nevertheless, the previously proposed hypothesis for the biology of Saurophthirus seems most plausible; it infers hematophagy on the wing membrane of pterosaurs and the gonotrophic cycle, as female returned into aquatic refuge after blood sucking.     

Promoters pro-SmAMP1 and pro-SmAMP2 from Wild Plant <Emphasis Type="Italic">Stellaria media</Emphasis> for the Biotechnology of Dicotyledons

Comparative results of the studied effectiveness of two new promoters, pro-SmAMP1 and pro- SmAMP2, from chickweed (Stellaria media L.) in various types of cultivated plants with transient expression and in stable transformants are given. The effectiveness of the promoters was evaluated through the expression of the reporter uidA gene by measuring the activity of its GUS protein product. It was found that the deletion variant (442 bp) of the pro-SmAMP1 promoter was significantly stronger in plants of Nicotiana benthamiana (Domin) with transient expression than the deletion variant (455 bp) of the pro-SmAMP2 promoter. The effectiveness of these short deletion variants of both promoters under transient expression in the plants of rapeseed (Brassica napus L.) and sugar beet (Beta vulgaris L.) was comparable with that of the viral CaMV35S promoter. The functionality of the pro-SmAMP2 promoter in the calluses of common flax plants (Linum usitatissimum L.) was shown. In the homozygous lines of transgenic tobacco plants (Nicotiana tabacum L.), all deletion variants of the pro-SmAMP1 promoter and the shortest version of pro-SmAMP2 were twice as strong as the CaMV35S viral promoter. The effectiveness of short variants of both promoters from the chickweed in controlling the gene encoding neomycin phosphotransferase II in the transgenic plants of tobacco and arabidopsis (Arabidopsis thaliana L.) growing on media supplemented with recommended concentrations of kanamycin are not inferior to the duplicated 2хCaMV35S viral promoter. The obtained experimental data show that short deletion variants of pro-SmAMP1 (442 bp) and pro-SmAMP2 (455 bp) promoters may be recommended as strong constitutive promoters for use in the biotechnology of crop plants.     

Down-regulation of the tumor suppressor gene C-terminal Src kinase: an early event during premalignant colonic epithelial hyperproliferation

Hyperproliferation of the premalignant epithelium is critical for colonic carcinogenesis; however the mechanisms remain largely unexplored. We report herein that prior to occurrence of neoplastic lesions in the azoxymethane-rat model of colon carcinogenesis; the tumor suppressor gene C-terminal Src kinase (Csk) was down-regulated with a concomitant increase in Src activity. Furthermore, pharmacological or genetic (RNA interference) inhibition of Csk resulted in increased proliferation in colon cancer cell lines through the mitogen-activated protein kinase dependent pathway. Thus, we demonstrate, for the first time, that Csk suppression is an important early event in colorectal cancer pathogenesis.     

Assessment of the Relative Biological Efficiency of Pencil Beam Scanning of Protons in Mice in Vivo

Doklady Biochemistry and Biophysics - The effect of proton pencil beam scanning in the dose range of 4.5–15 Gy on the radiosensitivity of mice under irradiation in two regions of the Bragg...     

The remote effects of radiation after hypofractionated irradiation with protons of Ehrlich ascites carcinoma in mice

This work focuses on the study of remote effects (duration of remission, recurrence rate, and average lifespan) in mice with Ehrlich ascites carcinoma exposed to oligofractionated irradiation with a pencil scanning beam of protons depending on the volume of the tissue being irradiated and the interval between dose fractions. The results show higher antitumor efficacy and a considerable increase in the average life span of mice after hypofractionated irradiation with a pencil scanning beam of protons at a total dose of 60 Gy of the gross tumor volume compared with the planning target volume.     

Bioorganic components and compounds of petroleum series in bottom sediments in Lake Tus and Lake Chyornoye (Khakassia)

The distribution of bioorganic components and compounds of anthropogenic and mixed origin in the bottom sediments (BSs) in freshwater Lake Chyornoye and saltwater Lake Tus (Republic of Khakassia) has been studied using the chromatographic mass spectrometric method. The contribution of the major organic matter sources to the BS composition is assessed. It is ascertained that the formation of the BS composition can mostly arise due to the compounds of biogenic and mixed origin. Some lake sites with elevated concentrations of pollutants—petroleum and pyrogenic hydrocarbons and iso-alkylbenzenes as the probable degradation products of surface-active agents—are identified.