Topography of rRNA in ribosomes. Effect of pancreatic RNAse on small ribosomal subunits]

The treatment of E. coli 30S ribosome subunits with pancreatic RNase under certain conditions resulted in the release of rRNA (about 15%). The subunit retained as a whole structure: sedimentation coefficient was unchanged and no protein release was observed. The released RNA is a set of oligonucleotides from 1 to 9 bases, except hepta- and octanenucleotides. Base composition of this RNA fraction is similar to 16S RNA, a slight increase of purines content being due to the specificity of nuclease. Analysis of isoplit content has revealed that a spliting of long oligonucleotides in stechiometric amount from 30S subunits takes place: one nonanucleotide, one hexanucleotide and two pentanucleotides.     

Heterotrophic organisms and viruses in the Oka River and Cheboksary Reservoir during the abnormally hot summer of 2010

In July 2010, abnormally high water temperature (25–29°C), as well as increased biomass and phytoplankton production caused intensive development of heterotrophic bacteria and heterotrophic nanoflagellates. It was found that the abundance, biomass, and production of heterotrophic bacterioplankton, as well as the abundance and biomass of heterotrophic nanoflagellates, and the number of planktonic viruses, which were calculated on average for the reservoir under study, turned out to be higher in the years with lower water temperature (20–23°C). The virus-induced mortality of bacterioplankton in the Oka River and the Cheboksary Reservoir averaged 25.4 ± 3.4 and 22.4 ± 2.7% of the daily bacterioplankton production.     

Severe Painful Vaso-Occlusive Crises and Mortality in a Contemporary Adult Sickle Cell Anemia Cohort Study

Background

Frequent painful vaso-occlusive crises (VOCs) were associated with mortality in the Cooperative Study of Sickle Cell Disease (CSSCD) over twenty years ago. Modern therapies for sickle cell anemia (SCA) like hydroxyurea are believed to have improved overall patient survival. The current study sought to determine the relevance of the association between more frequent VOCs and death and its relative impact upon overall mortality compared to other known risk factors in a contemporary adult SCA cohort.

Methods

Two hundred sixty four SCA adults were assigned into two groups based on patient reported outcomes for emergency department (ED) visits or hospitalizations for painful VOC treatment during the 12 months prior to evaluation.

Results

Higher baseline hematocrit (p = 0.0008), ferritin (p = 0.005), and HDL cholesterol (p = 0.01) were independently associated with 1 or more painful VOCs requiring an ED visit or hospitalization for acute pain. During a median follow-up of 5 years, mortality was higher in the ED visit/hospitalization group (relative risk [RR] 2.68, 95% CI 1.1-6.5, p = 0.03). Higher tricuspid regurgitatant jet velocity (TRV) (RR 2.41, 95% CI 1.5-3.9, p < 0.0001), elevated ferritin (RR 4.00, 95% CI 1.8-9.0, p = 0.001) and lower glomerular filtration rate (RR=2.73, 95% CI 1.6-4.6, p < 0.0001) were also independent risk factors for mortality.

Conclusions

Severe painful VOCs remain a marker for SCA disease severity and premature mortality in a modern cohort along with other known risk factors for death including high TRV, high ferritin and lower renal function. The number of patient reported pain crises requiring healthcare utilization is an easily obtained outcome that could help to identify high risk patients for disease modifying therapies.

Trial Registration

ClinicalTrials.gov NCT00011648 http://clinicaltrials.gov/     

Coexistence of G-quadruplex and duplex domains within the secondary structure of 31-mer DNA thrombin-binding aptamer

A number of thrombin-binding DNA aptamers have been developed during recent years. So far the structure of just a single one, 15-mer thrombin-binding aptamer (15TBA), has been solved as G-quadruplex. Structures of others, showing variable anticoagulation activities, are still not known yet. In this paper, we applied the circular dichroism and UV spectroscopy to characterize the temperature unfolding and conformational features of 31-mer thrombin-binding aptamer (31TBA), whose sequence has a potential to form G-quadruplex and duplex domains. Both structural domains were monitored independently in 31TBA and in several control oligonucleotides unable to form either the duplex region or the G-quadruplex region. The major findings are as follows: (1) both duplex and G-quadruplex domains coexist in intramolecular structure of 31TBA, (2) the formation of duplex domain does not change the fold of G-quadruplex, which is very similar to that of 15TBA, and (3) the whole 31TBA structure disrupts if either of two domains is not formed: the absence of duplex structure in 31TBA abolishes G-quadruplex, and vice versa, the lack of G-quadruplex folding results in disallowing the duplex domain.     

Trophic relationships between planktonic bacteria,heterotrophic nanoflagellates and viruses in a mesoeutrophic reservoir

The abundance, biomass, and production (Р _В) of bacrerioplankton; the taxonomic composition, abundance, biomass of heterotrophic nanoflagellates (HNF) and the rate of consumption of bacteria by HNFs; and the abundance of virioplankton, frequency of visibly infected bacterial cells, virus-induced mortality of bacterioplankton, and viral production were estimated in the mesoeutrophic Rybinsk Reservoir. The rate of bacterial mortality due to viral lysis (7.8–34.1%, on average 17.2 ± 2.0% of daily Р _В) was lower than the consumption of bacteria by the HNF community (15.4–61.3%, on average 32.0 ± 4.2% of daily Р _В). While consuming bacteria, HNFs simultaneously absorbed a significant number of viruses residing on the surface and inside the bacterial cells.     

The influence of viruses on bacterioplankton of the offshore and coastal parts of the Barents Sea

The viral and bacterioplankton communities of the Barents Sea were investigated using a combination of methods of electron and epifluorescence microscopy for the first time. The quantitative composition of the communities and the nature of their interactions were also determined. Our study showed that during the summer the abundance and biomass of bacterioplankton reached 0.4–4.0 × 10⁶ cells/mL and 25.09–84.21 mg/m³ in offshore waters and 0.4–1.8 × 10⁶ cells/mL and 19.63–100.19 mg/m³ in coastal waters, respectively. In both regions, the number of viruses (1.7–35.8 × 10⁶ and 14.5–32.4 × 10⁶ particles/mL) exceeded the number of bacteria by 2–31 and 13–60 times, respectively; the average viral production was 0.7510⁶ and 1.74 × 10⁶ particles/mL/day, respectively. The proportion of infected cells in the total bacterioplankton (7% on average) and virus-induced mortality of bacteria (8%) were much lower in offshore than in coastal waters (14 and 20%, respectively).