Analysis of omega-3 and omega-6 fatty acid-derived lipid metabolite formation in human and mouse blood samples

Mass spectrometry techniques have enabled the identification of different lipid metabolites and mediators derived from omega-6 and omega-3 polyunsaturated fatty acids (n-6 and n-3 PUFA) that are implicated in various biological processes. However, the broad-spectrum assessment of physiologically formed lipid metabolites and mediators in blood samples has not been presented so far. Here lipid mediators and metabolites of the n-6 PUFA arachidonic acid as well as the long-chain n-3 PUFA eicosapentaenoic acids (EPA) and docosahexaenoic acid (DHA) were measured in human blood samples as well as in mouse blood. There were detectable but mostly very low amounts of the assayed compounds in human native plasma samples, whereas in vitro activation of whole blood with the calcium ionophore A23187 led to highly significant increases of metabolite formation, with a predominance of the 12-lipoxygenase (12-LOX) products 12-hydroxyeicosatetraenoic acid (12-HETE), 12-hydroxyeicosapentaenoic acid (12-HEPE) and 14-hydroxydocosahexaenoic acid (14-HDHA). A23187 activation also led to significant increases in the formation of 5-LOX products including leukotriene B(4) (LTB(4)), leukotriene B(5) (LTB(5)) as well as of 15-LOX products and prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TXB(2)). Levels were similar or even higher in A23187-activated mouse blood. The approach presented here thus provides a protocol for the comprehensive and concomitant assessment of the generation capacity of n-3 and n-6 PUFA-derived lipid metabolites as well as thromboxanes and prostaglandins in human and murine blood samples. Further studies will now have to evaluate lipid metabolite generation capacity in different physiological and pathophysiological contexts.     

Palaeobiogeographic implications of the first report of the eocrinoid genus Ascocystites Barrande (Echinodermata,Blastozoa) in the Upper Ordovician of the Ougarta Range (Western Algeria)

Several specimens of the genus Ascocystites (Blastozoa, Eocrinoidea) are described for the first time in Late Ordovician deposits (Bou M’Haoud Formation) from the Ougarta Range, Algeria. This genus was previously known in Darriwilian–Sandbian deposits of four other areas of the Mediterranean Province (Czech Republic, France, Morocco and Portugal). The Algerian material completes its palaeobiogeographic distribution in the peri-Gondwanan area, restricted in shallow water settings.     

Proteomics of Protein Secretion by Bacillus subtilis: Separating the “Secrets” of the Secretome

Secretory proteins perform a variety of important “remote-control” functions for bacterial survival in the environment. The availability of complete genome sequences has allowed us to make predictions about the composition of bacterial machinery for protein secretion as well as the extracellular complement of bacterial proteomes. Recently, the power of proteomics was successfully employed to evaluate genome-based models of these so-called secretomes. Progress in this field is well illustrated by the proteomic analysis of protein secretion by the gram-positive bacterium Bacillus subtilis, for which ~90 extracellular proteins were identified. Analysis of these proteins disclosed various “secrets of the secretome,” such as the residence of cytoplasmic and predicted cell envelope proteins in the extracellular proteome. This showed that genome-based predictions reflect only ~50% of the actual composition of the extracellular proteome of B. subtilis. Importantly, proteomics allowed the first verification of the impact of individual secretion machinery components on the total flow of proteins from the cytoplasm to the extracellular environment. In conclusion, proteomics has yielded a variety of novel leads for the analysis of protein traffic in B. subtilis and other gram-positive bacteria. Ultimately, such leads will serve to increase our understanding of virulence factor biogenesis in gram-positive pathogens, which is likely to be of high medical relevance.     

Perceived and Physiological Indicators of Relaxation: As Different as Mozart and Alice in Chains

The effects of listening to different types of music on perceived and physiological indicators of relaxation were evaluated. Fifty-six undergraduate students, 24 males and 32 females, mean age of 21, were randomly assigned to listen to classical, hard rock, self-selected relaxing music, or no music. Participants' relaxation level, skin temperature, muscle tension and heart rate were evaluated before and after exposure to a music condition. Analyses of variance using baseline measures as covariates indicated that skin temperature decreased for all conditions (p = 0.001) and the classical, self-selected relaxing music and no music groups reported significant increases in feelings of relaxation (p = 0.004). These results partially support the hypothesis that classical and self-selected relaxing music can increase perceptions of relaxation to a greater degree than listening to hard rock music. However, no differences were found between different types of music on physiological indicators of arousal. Implications for using music to reduce stress were discussed.     

Ecological study of social fragmentation,poverty, and suicide

ObjectivesTo investigate the association between suicide and area based measures of deprivation and social fragmentation.DesignEcological study.Setting633 parliamentary constituencies of Great Britain as defined in 1991.ResultsMortality from suicide and all other causes increased with increasing Townsend deprivation score, social fragmentation score, and abstention from voting in all age and sex groups. Suicide mortality was most strongly related to social fragmentation, whereas deaths from other causes were more closely associated with Townsend score. Constituencies with absolute increases in social fragmentation and Townsend scores between 1981 and 1991 tended to have greater increases in suicide rates over the same period. The relation between change in social fragmentation and suicide was largely independent of Townsend score, whereas the association with Townsend score was generally reduced after adjustment for social fragmentation.ConclusionsSuicide rates are more strongly associated with measures of social fragmentation than with poverty at a constituency level.

Key messages

• Place of residence may affect health, and mortality from most common diseases tends to be higher in areas characterised by low socioeconomic position
• Research dating back over 100 years suggests that social fragmentation may influencesuicide
• In the 1980s and 1990s, parliamentary constituencies with high levels of social fragmentation had high rates of suicide, independent of deprivation
• Constituencies with the greatest increases in social fragmentation between 1981 and 1991 also had the greatest increases in suicide rates over the same period
• Any targeting of suicide prevention may be more effective if aimed at socially fragmented rather than deprived areas

     

Distribution of Tetracycline Resistance Genes and Transposons among Phylloplane Bacteria in Michigan Apple Orchards

The extent and nature of tetracycline resistance in bacterial populations of two apple orchards with no or a limited history of oxytetracycline usage were assessed. Tetracycline-resistant (Tc^r) bacteria were mostly gram negative and represented from 0 to 47% of the total bacterial population on blossoms and leaves (versus 26 to 84% for streptomycin-resistant bacteria). A total of 87 isolates were screened for the presence of specific Tc^r determinants. Tc^r was determined to be due to the presence of Tet B in Pantoea agglomerans and other members of the family Enterobacteriacae and Tet A, Tet C, or Tet G in most Pseudomonas isolates. The cause of Tc^r was not identified in 16% of the isolates studied. The Tc^r genes were almost always found on large plasmids which also carried the streptomycin resistance transposon Tn5393. Transposable elements with Tc^r determinants were detected by entrapment following introduction into Escherichia coli. Tet B was found within Tn10. Two of eighteen Tet B-containing isolates had an insertion sequence within Tn10; one had IS911 located within IS10-R and one had Tn1000 located upstream of Tet B. Tet A was found within a novel variant of Tn1721, named Tn1720, which lacks the left-end orfI of Tn1721. Tet C was located within a 19-kb transposon, Tn1404, with transposition genes similar to those of Tn501, streptomycin (aadA2) and sulfonamide (sulI) resistance genes within an integron, Tet C flanked by direct repeats of IS26, and four open reading frames, one of which may encode a sulfate permease. Two variants of Tet G with 92% sequence identity were detected.     

Limiting processes for perennial plant reintroduction to restore dry grasslands

In restored grasslands of southern Europe, perennial plants remain highly underrepresented compared with the reference ecosystems. We tested various treatments to reintroduce common perennial plant species (Brachypodium retusum, Poaceae, and Thymus vulgaris, Lamiaceae), which are usually not or poorly reintroduced via soil and hay transfer. Treatments included microenvironmental manipulations (rock cover and plant interactions) and two grazing intensities. Target perennial species were transplanted in 2002 in the reference grassland ecosystem (intact grassland area used as a control) and in two abandoned fields. Survival was assessed in June 2003 and June 2004. Target species shoot and root biomass were measured in June 2004. Grazing greatly reduced the survival and biomass of both target species and its effects were reinforced by summer drought: plants that did not establish well enough during the autumn and spring did not survive summer. The restored rock cover had a mild positive effect, particularly on B. retusum. There were no negative or positive plant neighbor interactions in the steppe, while there was competition in both abandoned fields. Competition was particularly intense in the abandoned melon field, composed of a dense sward of annual grasses (Bromus sp.). In order to reintroduce perennial species to dry grasslands, the ideal combination of treatments is to exclude or reduce grazing during the first year to allow seedlings to establish and to recreate adequate microenvironmental conditions. Reducing competition from arable weeds may help but is not essential in such dry grasslands.