Seasonal variability of lipids and fatty acids in the tree-growing lichen Xanthoria parientina L.

The composition of lipids, PLs and FAs in the treegrowing lichenXanthoria parientina, collected during the period from Marchto May, was studied. The major polar lipids found, includingphospholipids, were DGTS, PC, PE, and PG. Polar and PL contentswere also identified, and certain trends in the changing proportionsof PC (increasing from 17.8 to 50.1%) and DGTS (decreasing from27.1 to 12.6%) were determined. The fatty acid composition wasexamined using capillary GC-MS in the neutral, glyco- and PLfractions. Hydroxy acids were detected only in the glycolipidfraction; their seasonal dynamics were also studied. The seasonalchanges occurring in lipid composition due to the temperaturefactor were identified. It was found that X. parientina hada characteristic temperature-based lipid pattern, increasingin its neutral lipid content from 40.6% in March to 52.7% inMay but decreasing in glycolipid from 39.0% in March to 27.0%in May. Key words: Xanthoria, lipids, DGTS, fatty acids, lichen     

Mouse and Fly Sperm Motility Changes Differently under Modelling Microgravity

Sperm motility is essential for the natural fertilization process in most animal species. Despite the fact that evolution took place under conditions of constant gravity, the motility of spermatozoa of insects and mammals under microgravity conditions changes in different ways. In this work, an attempt was made to explain this effect. The sperm motility of the fruit fly Drosophila melanogaster and the mouse was evaluated after exposure to a random positioning machine for 6 h. Sodium fluoride was used to inhibit serine/threonine phosphatases, sodium orthovanadate was used to inhibit tyrosine phosphatases, and 6-(dimethylamino)purine was used to inhibit protein kinases. The results obtained indicate that simulated microgravity leads to an increase in the speed of movement of fly spermatozoa by 30% (p < 0.05), and this effect is blocked by sodium fluoride. In contrast, a 29% (p < 0.05) decrease in the speed of movement of mouse spermatozoa under simulated microgravity is prevented by 6-(dimethylamino)purine. Moreover, after 6 h of exposure, the content of tubulin cytoskeleton and actin proteins remains at the control level in the spermatozoa of flies and mice. However, the content of the actin-binding protein alpha-actinin in fly sperm decreases by 29% (p < 0.05), while in mouse sperm, the relative content of alpha-actinin1 increases by 94% (p < 0.05) and alpha-actinin4 by 121% (p < 0.05) relative to the control, as determined by 6 simulated microgravity tests. It can be assumed that the effect of simulated microgravity on the motility of mammalian spermatozoa is mediated through the regulation of phosphorylation and that of insects through the regulation of dephosphorylation of motor proteins; moreover, the development of a response to changes in external mechanical conditions has a different time scale.     

The new vaccine strains (or variants) of Francisella tularensis

Abstract A colony (N83) of the vaccine strain of Francisella tularensis (15/10) and a strain (N268) isolated from a water sample in nature were revealed for susceptibility to cultivation at 42°C. Both strains had low virulence for white mice and were avirulent for guinea pigs but possessed high immunogenicity in these animals. The spontaneous mutant of vaccine strain 15/10 showed resistance to doxicycline and rifmanpicine (15/10 Dox ^r40 Rif ^r40). The obtained mutant had biological characteristics similar to the parent vaccine strain. It provided immunity in experimental animals when vaccination and antimicrobial agents were used in combination.     

Comparative evaluation of gene-set analysis methods

Background  

Multiple data-analytic methods have been proposed for evaluating gene-expression levels in specific biological pathways, assessing differential expression associated with a binary phenotype. Following Goeman and Bühlmann's recent review, we compared statistical performance of three methods, namely Global Test, ANCOVA Global Test, and SAM-GS, that test "self-contained null hypotheses" Via. subject sampling. The three methods were compared based on a simulation experiment and analyses of three real-world microarray datasets.     

Repair of sequence-specific 125I-induced double-strand breaks by nonhomologous DNA end joining in mammalian cell-free extracts

In mammalian cells, nonhomologous DNA end joining (NHEJ) is considered the major pathway of double-strand break (DSB) repair. Rejoining of DSB produced by decay of (125)I positioned against a specific target site in plasmid DNA via a triplex-forming oligonucleotide (TFO) was investigated in cell-free extracts from Chinese hamster ovary cells. The efficiency and quality of NHEJ of the "complex" DSB induced by the (125)I-TFO was compared with that of "simple" DSB induced by restriction enzymes. We demonstrate that the extracts are indeed able to rejoin (125)I-TFO-induced DSB, although at approximately 10-fold decreased efficiency compared with restriction enzyme-induced DSB. The resulting spectrum of junctions is highly heterogeneous exhibiting deletions (1-30 bp), base pair substitutions, and insertions and reflects the heterogeneity of DSB induced by the (125)I-TFO within its target site. We show that NHEJ of (125)I-TFO-induced DSB is not a random process that solely depends on the position of the DSB but is driven by the availability of microhomology patches in the target sequence. The similarity of the junctions obtained with the ones found in vivo after (125)I-TFO-mediated radiodamage indicates that our in vitro system may be a useful tool to elucidate the mechanisms of ionizing radiation-induced mutagenesis and repair.     

A beta-galactose-specific lectin isolated from the marine worm Chaetopterus variopedatus possesses anti-HIV-1 activity

A 30 kDa beta-galactose-specific lectin named CVL was isolated from the polychaete marine worm Chaetopterus variopedatus (Annelida) and its anti-HIV-1 activity in vitro was determined. Results showed that CVL inhibited cytopathic effect induced by HIV-1 and the production of viral p24 antigen. The EC(50) values were 0.0043 and 0.057 microM, respectively. Time-of-addition analysis of anti-HIV-1 activity indicated its action was at the early stage of virus replication. CVL could blocked the cell-to-cell fusion process of HIV infected and uninfected cells with an EC(50) of 0.073 microM. The inhibition of HIV-1 entry into host cells was demonstrated by using fluorescence-based real-time quantify PCR. At CVL concentration of 0.33 microM and 0.07 microM, 86% and 21% virus attachment were blocked, respectively. The anti-HIV-1 action of CVL might relate to blockade of HIV-1 entry into cells.