Stereochemical course of the hydroboration of highly hindered steroidal olefins. A ready synthesis of 14 beta- and 8 alpha,14 beta-steroids

Hydroboration of 5 alpha-cholest-8-ene, 5 alpha,14 beta-cholest-8-ene and 5 alpha,14 beta-cholest-7-ene provides a simple route to oxygenated steroids with 14 beta- and 8 alpha,14 beta- unnatural stereochemistry.     

Alpha-helical small molecular size analogues of neuropeptide Y: structure-activity relationships.

C-terminal analogues of neuropeptide Y (NPY) of small molecular size have been synthesized. The influence of chain length, single or multiple amino acid substitution, and segment substitutions on receptor binding, pre- and postsynaptic biological activity, and conformational properties have been investigated. Receptor binding and in vivo assays revealed biological activity for NPY Ac-25-36 that increased with increasing alpha-helicity. In attempts to stabilize the alpha-helical content, three independent types of modified NPY Ac-25-36 analogues were synthesized. Strong agonistic activities could be detected in a series of discontinuous analogues, which are constructs of N-terminal parts linked via different spacer molecules to C-terminal segments. One of the most active molecules was NPY 1-4-Aca-25-36 (Aca, epsilon-aminocaproic acid). For the first time conformational properties of a series of small NPY analogues have been investigated by CD, and correlated with biological activity and receptor binding. A C-terminal dodecapeptide segment of NPY with an amount of 50% substitution to the native C-terminal sequence of NPY was found to exhibit significant receptor binding.     

The distance dependence prediction of the Janzen-Connell hypothesis: a meta-analysis

The Janzen-Connell hypothesis explains the maintenance of tropical diversity through the interacting effects of parent-centered dispersal patterns and distance- and density-dependent propagule survival. These effects were thought to support regular spacing of species within tropical forest, enhancing diversity. One of the predictions of the hypothesis is that seed and seedling survival should improve with increased parental distance. Although there are many independent tests of this hypothesis for individual species, there are few synthetic studies that have brought these data together to test its validity across species. This paper reports the results of a meta-analysis of the effect of distance on enhancing propagule survival, employing an odds-ratio effect size metric. We found no general support for the distance-dependent prediction of the hypothesis, and conclude that further testing to explore this hypothesis as a diversity-maintaining mechanism is unnecessary. However, we did find that distance from parent slightly reduces survivorship in the temperate zone, as contrasted with the tropics, and we saw stronger evidence in support of the hypothesis for seedlings than for seeds. The phenomenon of enhanced propagule survival with distance from the parent may be important for the population biology of particular species, but it is not a general phenomenon across communities, life history stages or life forms.     

Correction to: Sex and race differences of cerebrospinal fluid metabolites in healthy individuals

Metabolomics - Metabolomics applications to the aquaculture research are increasing steadily. The use of standardized proton nuclear magnetic resonance (1H NMR) spectroscopy can provide the...     

Phytogeographical affinities at the crossroads of two continents: Distribution patterns of Lamiaceae in Chios Island (East Aegean Islands,Greece) and Çeşme–Karaburun Peninsula (West Anatolia,Turkey)

The East Aegean (East Aegean Islands, Greece and West Anatolia, Turkey) is a biogeographically transitional region, where biodiversity elements from Europe and Asia join. However, affinities in the region were until recently scarcely explored. We assess biogeographical affinities in the East Aegean focusing on distribution patterns of Lamiaceae plants in Chios Island and its adjacent Çe?me–Karaburun Peninsula. Detailed in-situ record was acquired for 48 native species. These were grouped based on their habitat and geological substrate preference, their distribution was mapped in grid cells and distribution patterns were analysed in relation to species groupings. In both Chios and Çe?me–Karaburun, species follow five distribution patterns: widespread, locally widespread, locally restricted, sporadic and rare. Fifty to 62% of the species exhibit similar distribution patterns, trends in habitat and geological substrate preference in Chios and Çe?me–Karaburun, results complying with previous evidence of close biogeographical affinities of the East Aegean Islands and neighbouring Anatolia. Differences observed between the two regions may be attributed to insularity effects, human impact and the melange, an old rock matrix known for its key role in elucidating regional geodynamic evolution. Distributions of widespread and locally widespread species in Chios give evidence of density compensation and niche shifts responses, however, the actual occurrence of these phenomena in island plant populations is still to be elucidated. Overall, the species distribution patterns, particularly those of rare ones, reflect the complex geological history, palaeogeography and human influence in the Aegean region.     

Surfactant Protein A Binds Flagellin Enhancing Phagocytosis and IL-1β Production

Surfactant protein A (SP-A), a pulmonary collectin, plays a role in lung innate immune host defense. In this study the role of SP-A in regulating the inflammatory response to the flagella of Pseudomonas aeruginosa (PA) was examined. Intra-tracheal infection of SP-A deficient (SP-A-/-) C57BL/6 mice with wild type flagellated PA (PAK) resulted in an increase in inflammatory cell recruitment and increase in pro-inflammatory cytokines IL-6 and TNF-α, which was not observed with a mutant pseudomonas lacking flagella (fliC). SP-A directly bound flagellin, via the N-linked carbohydrate moieties and collagen-like domain, in a concentration dependent manner and enhanced macrophage phagocytosis of flagellin and wild type PAK. IL-1β was reduced in the lungs of SP-A-/- mice following PAK infection. MH-s cells, a macrophage cell line, generated greater IL-1β when stimulated with flagellin and SP-A. Historically flagella stimulate IL-1β production through the toll-like receptor 5 (TLR-5) pathway and through a caspase-1 activating inflammasome pathway. IL-1β expression became non-detectable in SP-A and flagellin stimulated MH-s cells in which caspase-1 was silenced, suggesting SP-A induction of IL-1β appears to be occurring through the inflammasome pathway. SP-A plays an important role in the pathogenesis of PA infection in the lung by binding flagellin, enhancing its phagocytosis and modifying the macrophage inflammatory response.