Synthesis and properties of cross-linked DNA duplexes

AbstractA method has been devised to synthesize DNA duplexes with covalently connected strands. The structure of cross-linked duplexes was confirmed by a reaction with the restriction endonuclease AluI. The thermal stability of the resulting compounds was investigated

Influence of probe structure on unique (regiospecific) cleavage of RNA by RNase H

AbstractChimeric oligo(ribo-deoxyribo)nucleotides with an internucleotide pyrophosphate bond are novel probes for regiospecific hydrolysis of RNA by RNase H. It has been shown that the use of d(TGTGTAT)ppGCCAU leads to unique hydrolysis of the TMV RNA fragment pAAUGGCAUACAC between C10 and A11

Ctenophores-invaders and their role in the trophic dynamics of the planktonic community in the coastal regions off the Crimean coasts of the Black Sea (Sevastopol Bay)

The abundances, biomasses, and population structures of two introduced ctenophore species-Mnemiopsis leidyi and Beroe ovata-were monitored along with mesoplankton in the near-shore waters of the northern Black Sea (Sevastopol Bay and adjacent regions) over a period of four years (2000-2003), after the B. ovata invasion. The annual dynamics of the M. leidyi population were similar in these years: very low abundances and biomass values were observed during the major part of the year ( unlike previous years) with a short-term peak in the summer-early autumn. B. ovata development during the growth in the M. leidyi biomass resulted in a sharp fall in the M. leidyi biomass down to extremely low values. The interannual differences in the populations of both ctenophore species were reflected by their quantitative parameters: the maximum biomass of M. leidyi varied from 790 g/m(2) in 2001 to 211-266 g/m(2) in other years. The maximum biomass values of B. ovata (38.9 and 32.5 g/m(2)) were observed in 2001 and 2003, respectively. In 2000-2003, from July to September, during the peak in mnemiopsis development, the population consumed from 1.9 +/- 0.4 to 13.4 +/- 5.7% of the mesoplankton biomass per day, while in the years of B. ovata absence, these values were as high as 30-40%. For the first time, the grazing rate of microzooplankton by M. leidi larvae was estimated. In August 2003, the maximum daily consumption rate was as great as 23-25% of the microzooplankton biomass. The daily rations of the mnemiopsis larvae on microzooplankton were close or even higher than those on mesoplankton