Expression of the nif and ntr genes of Klebsiella pneumoniae in Rhodobacter sphaeroides cells

The genes glnA, ntr, nif or their promoters from Klebsiella pneumoniae cloned on the vectors, based on the plasmid RSF1010, were introduced into Rhodobacter sphaeroides cells. It was found that K. pneumoniae genes glnA, nifB, nifE, nifL and nifH are not expressed in R. sphaeroides. Neither was the glnA gene from cyanobacterium Anabaena 7120 expressed in R. sphaeroides. No functional activity of K. pneumoniae product of ntrA gene which is expressed from its own promoter, and the product of the gene nifA which is expressed from the constitutive promoter of the kanamycin resistance gene of the transposon Tn903, was detected. The implications of these findings are discussed.     

Hydroxyl radical generation by oligonucleotide derivatives of anthracycline antibiotic and synthetic quinone.

For the first time the covalent binding of anticancer anthracycline drugs and their potential synthetic analogs to oligonucleotides of different sequences is proposed for obtaining site-specific DNA scission in systems in vitro and in vivo. New compounds such as daunomycin (Dm) and synthetic naphthoquinone (NQ), covalently bound to the heptadeoxynucleotide of pCCAAACA (Dm-pN7) and decadeoxythymidilate (pT10p-NQ), have been obtained. These oligonucleotide derivatives can form specific complexes with complementary oligonucleotide sequences; these compounds and their complementary complexes can be reduced by purified NADPH-cytochrome P-450 reductase. Using the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO), it has been shown that in aerobic conditions Dm-pN7 and pT10p-NQ are capable of generating OH radicals with and without complementary oligonucleotides. The chemical stability of the compounds in redox reactions has been studied. Oligonucleotide derivatives of natural and synthetic quinones capable of generating OH radicals seem to be a promising tool for site-specific scission of DNA in solution and in cells.     

Polychaeta of the Kara and Pechora seas: Data of the 2012 trawl survey

The species composition of the polychaetes derived from ichthyological and Sigsbee trawls in the Pechora and Kara seas in 2012 was studied and compared with the grab survey data of 1993–1995. The distribution of the large sabellidae, nektobenthic, and bathypelagic species that are poorly caught by a grab has been determined for the first time. Changes that were observed in the biogeographical polychaete structure in the Kara Sea (a higher proportion of the boreal species and a lower proportion of the Arctic species) may reflect a response of zoobenthos to the Arctic warming in the late 20th and early 21st centuries.     

Optimization of a genome-wide disordered lentivector-based short hairpin RNA library

To obtain a whole genome library that suppresses the total diversity of human mRNAs, lentiviral vector constructs and a short hairpin RNA (shRNA) expression cassette were optimized. The optimization of the vector increased the virus titer in preparations by 15–20 times. A simple shRNA structure with a 21-bp stem proved to be the most effective. Lentivector-based shRNA expression constructs were obtained by using puro ^R, copGFP, or H-2K ^k as a selectable marker. The efficiency of the optimized library was demonstrated when screening for shRNAs reactivating the tumor suppressor p53 in HeLa cells. Cells carried a reporter construct ensuring p53-responsive synthesis of a fluorescent protein, which allowed selection of cells with reactivated p53 by flow cytometry.