Effect of Gene Silencing of Translation Initiation Factors eIF(iso)4G and eIF(iso)4E on Sour Cherry Rootstock Resistance to Sharka Disease

Sharka disease, caused by the Plum pox virus (PPV), is one of the most harmful, quarantine viral diseases that affect stone fruit crops. The absence of natural resistance to the virus in stone fruits has become a decisive factor for the use of genetic transformation methods to obtain stable forms. The eIF(iso)4G and eIF(iso)4E genes encode translation initiation factors used in the PPV life cycle. In the presented study, the effect of silencing these genes using the RNA interference method on the resistance of sour cherry rootstock 146-2 plants (Prunus pumila L. x Prunus tomentosa Thunb) to the sharka disease was studied. Two vectors have been created for the genetic transformation of plants, with self-complementary sequences of the eIF(iso)4G and eIF(iso)4E gene fragments. The hairpin expression cassette contains a strong promoter of the peach ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) gene, as well as an intron and terminator of the same gene. We used the pMF1 vector containing recombinase R and a codA-nptII gene which makes it possible to obtain intragenic marker-free plants. A successful genetic transformation was carried out by the AGL0 strain of A. tumefaciens. Whole leaves of shoots cultivated in vitro were used as a source of explants. Eight independent transgenic lines of rootstock 146-2 were obtained in experiments (sixlines with a hairpin to the eIF(iso)4G gene and two lines with a hairpin to the eIF(iso)4E gene). Their status was confirmed by the PCR and Southern blotting. The obtained plants were acclimatized in a greenhouse. The silencing of the eIF(iso)4G and eIF(iso)4E genes in transgenic plants was confirmed by the quantitative PCR. The presence of specific small interfering (si) RNAs was confirmed by the method of Northern blotting. Plants of all transgenic rootstock lines were infected with PPV by the method of grafting with infected buds. Resistance to the PPV infection of the obtained transgenic plants was carried out by using an enzyme immunoassay. The ELISA results showed that silencing the eIF(iso)4G gene did not lead to increased resistance while silencing the eIF(iso)4E factor gene led to increased resistance to the PPV, and the one line’s plants showed no signs of infection for two years after infecting. The work demonstrates a (promising) approach in which the creation of stone cultures resistant to the plum pox virus can be achieved by suppressing the genes of translation initiation factors in clonal rootstocks.     

Non-Noble-Metal Mono and Bimetallic Composites for Efficient Electrocatalysis of Phosphine Oxide and Acetylene C-H/P-H Coupling under Mild Conditions

The present work describes an efficient reaction of electrochemical phosphorylation of phenylacetylene controlled by the composition of catalytic nanoparticles based on non-noble-metals. The sought-after products are produced via the simple synthetic protocol based on room temperature, atom-economical reactions, and silica nanoparticles (SNs) loaded by one or two d-metal ions as nanocatalysts. The redox and catalytic properties of SNs can be tuned with a range of parameters, such as compositions of the bimetallic systems, their preparation method, and morphology. Monometallic SNs give phosphorylated acetylene with retention of the triple bond, and bimetallic SNs give a bis-phosphorylation product. This is the first example of acetylene and phosphine oxide C-H/P-H coupling with a regenerable and recyclable catalyst.     

Finite line-source model for borehole heat exchangers: effect of vertical temperature variations

A solution to the three-dimensional finite line-source (FLS) model for borehole heat exchangers (BHEs) that takes into account the prevailing geothermal gradient and allows arbitrary ground surface temperature changes is presented. Analytical expressions for the average ground temperature are derived by integrating the exact solution over the line-source depth. A self-consistent procedure to evaluate the in situ thermal response test (TRT) data is outlined. The effective thermal conductivity and the effective borehole thermal resistance can be determined by fitting the TRT data to the time-series expansion obtained for the average temperature.     

Integration of purple non-sulfur bacteria into the starch-hydrolyzing consortium

Purple non-sulfur bacteria Rhodobacter sphaeroides N7 was integrated into the heterotrophic starch-hydrolyzing consortium containing Clostridium butyricum as the main component. The resulting light-dependent consortium with Bchl ∼9 μg/ml was maintained during 12 months of regular transfers. The protein content in this consortium was four-fold higher compared to the heterotrophic consortium, suggesting that purple bacteria became its important component. Under illumination, the starch hydrolysis by the light-dependent consortium (as opposed to heterotrophic consortium) resulted in the absence of VFAs, hydrogen production being quite similar and residual hexose higher. Fermentation of glucose (unlike to starch) by the light-dependent consortium or Rb. sphaeroides alone resulted in ∼3 fold increase of hydrogen production compared to the heterotrophic consortium. Apparently, hydrolysis of starch to hexose was the bottleneck in H₂ photoproduction by the light-dependent consortium. Availability of residual hexose after photofermentation of starch/glucose by the light-dependent consortium or Rb. sphaeroides is discussed.     

Thermodynamic Analysis and Experimental Study of Composite Structure Formation in Eutectic Alloys α -Al + Mg2Si

The Al ― Mg ― Si phase diagram was studied and the formation conditions for a regular two-phase eutectic structure (α-Al + Mg₂Si) were established. Concentration limits were found for optimum alloy compositions with maximum melting point (～595°C) and a narrow (or zero) melting (crystallization) range (less than 5°C). The structures of these alloys are formed by Mg₂Si monocrystal fibers and lamellae with a high degree of ordering, located in the aluminum matrix.     

How To Form a Phosphate Anhydride Linkage in Nucleotide Derivatives

The fundamental roles of nucleoside triphosphates and nucleotide cofactors such as NAD⁺ in biochemistry are well known. In recent decades, continuing research has revealed the key role of 5′‐capped RNA and 5′,5′‐dinucleoside polyphosphates in the regulation of vitally important physiological processes. Last but not least, the commercial potential of nucleoside triphosphate synthesis can hardly be overestimated. Nevertheless, despite decades of investigation and the obvious topicality of the research on the chemical synthesis of the nucleotide compounds containing phosphate anhydride linkages, none of the existing procedures can be considered an up‐to‐date “gold standard”. However, there are a number of fruitful synthetic approaches to forming phosphate anhydride linkages in satisfactory yield. These are summarized in this concise review, organized by the type of active phosphorous intermediate and reagents used.     

Polyphosphoester‐based paclitaxel complexes

We demonstrated a feasible approach for the preparation of a biodegradable, water soluble polyphosphoester based paclitaxel complex. Applying poly(hydroxyoxyethylene phosphate) which contains both a strong proton accepting P?O group and a proton donating P? OH group, paclitaxel has been physically immobilized onto the polymer via H‐bonding. The water soluble complex contained 16.7 wt % paclitaxel and more than 4000 times increased drug solubility was achieved. The polymer‐drug complex formed nanosized aggregates that were characterized by dynamic light scattering. Intravenous injection of poly(hydroxyoxyethylene phosphate) in rats at a dose of 1000 mg/kg did not induce any clinical signs or body weight gain reduction. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42772.     

Structural Analysis of the Ancestral Haloalkane Dehalogenase AncLinB-DmbA

Haloalkane dehalogenases (EC 3.8.1.5) play an important role in hydrolytic degradation of halogenated compounds, resulting in a halide ion, a proton, and an alcohol. They are used in biocatalysis, bioremediation, and biosensing of environmental pollutants and also for molecular tagging in cell biology. The method of ancestral sequence reconstruction leads to prediction of sequences of ancestral enzymes allowing their experimental characterization. Based on the sequences of modern haloalkane dehalogenases from the subfamily II, the most common ancestor of thoroughly characterized enzymes LinB from Sphingobium japonicum UT26 and DmbA from Mycobacterium bovis 5033/66 was in silico predicted, recombinantly produced and structurally characterized. The ancestral enzyme AncLinB-DmbA was crystallized using the sitting-drop vapor-diffusion method, yielding rod-like crystals that diffracted X-rays to 1.5 Å resolution. Structural comparison of AncLinB-DmbA with their closely related descendants LinB and DmbA revealed some differences in overall structure and tunnel architecture. Newly prepared AncLinB-DmbA has the highest active site cavity volume and the biggest entrance radius on the main tunnel in comparison to descendant enzymes. Ancestral sequence reconstruction is a powerful technique to study molecular evolution and design robust proteins for enzyme technologies.