Transient receptor potential, TRP channels: a new family of channels broadly expressed

Transient receptor potential, TRP channels are a new superfamily of functionally versatile non-selective cation channels present from yeast to mammals. On the basis of their structural homology, TRP channels are subdivided in 7 groups : TRPC 1-7 Canonical, TRPV 1-6 Vanilloid, TRPM 1-8 Melastatin, TRPP 1-3 Polycystin, TRPML Mucolipin, TRPA Ankyrin and TRPN (NO mechanotransducer potential C), the latter not expressed in mammals. Their cloning and heterologous expression allowed to demonstrating that these channels are generally weakly voltage-dependent. They are activated by various ligands involving a signal transduction cascade as well as directly by multiple compounds, heat and pH. TRP channels are found in a broad range of cell types. TRP channels are essential in allowing animals to sense the outside world and cells to sense their local environment. Following mutations or anomalous behaviour, these channels have a major role in several human diseases.     

Similar ectopic gene conversion frequencies in the backbone genome of pathogenic and nonpathogenic Escherichia coli strains

We previously showed that gene conversions were more frequent in the genomes of three Escherichia coli pathogenic strains than in the genome of the nonpathogenic K-12 E. coli strain. However, that study did not address whether the more frequent conversions observed in the genes of pathogenic strains occurred between the backbone genes common to these four strains or in the numerous horizontally transferred genes found only in pathogenic strains. Here, we show that ectopic gene conversions are equally frequent in the backbone genes of pathogenic and nonpathogenic strains, that most of these conversions are short, and that the nucleotide changes they generate are probably selectively neutral. Backbone genes are therefore under similar selective constraints in both pathogenic and nonpathogenic E. coli strains. The higher frequency of gene conversions we previously observed in pathogenic strains is therefore due to higher conversion frequencies between the numerous horizontally transferred genes found only in pathogenic strains.     

A yeast PAF acetylhydrolase ortholog suppresses oxidative death

Phospholipids containing sn-2 polyunsaturated fatty acyl residues are primary targets of oxidizing radicals, producing proapoptotic and membrane perturbing fragmented phospholipids. The only known phospholipases that specifically select these oxidized and/or short-chained phospholipids as substrates are mammalian group VII phospholipases A2s that were purified and cloned as PAF acetylhydrolases. Platelet-activating factor (PAF) is a short-chained phospholipid, and whether these enzymes actually are PAF hydrolases or evolved as oxidized phospholipid phospholipases is unknown. The fission yeast Schizosaccharomyces pombe, which does not form or use PAF as a signaling molecule, contains an open-reading frame potentially homologous to mammalian group VII phospholipase A2s. We cloned this SPBC106.11c locus and expressed it in distantly related Saccharomyces cerevisiae that lack homologous sequences. The S. pombe locus encoded a functional phospholipase A2, now renamed plg7+, that hydrolyzed PAF and a synthetic oxidized phospholipid. Expression of human type II PAF acetylhydrolase or S. pombe Plg7p enhanced the viability of S. cerevisiae subjected to oxidative stress. We conclude that a single-celled organism with an exceedingly spare genome still expresses an unusually discriminating phospholipase A2, and that selective hydrolysis of phospholipid oxidation products is an early, and critical, way to overcome oxidative membrane damage and oxidant-induced cell death.     

Major quantitative trait loci affect resistance to infectious pancreatic necrosis in Atlantic salmon (Salmo salar)

Infectious pancreatic necrosis (IPN) is a viral disease currently presenting a major problem in the production of Atlantic salmon (Salmon salar). IPN can cause significant mortality to salmon fry within freshwater hatcheries and to smolts following transfer to seawater, although challenged populations show clear genetic variation in resistance. To determine whether this genetic variation includes loci of major effect, a genomewide quantitative trait loci (QTL) scan was performed within 10 full-sib families that had received a natural seawater IPN challenge. To utilize the large difference between Atlantic salmon male and female recombination rates, a two-stage mapping strategy was employed. Initially, a sire-based QTL analysis was used to detect linkage groups with significant effects on IPN resistance, using two to three microsatellite markers per linkage group. A dam-based analysis with additional markers was then used to confirm and position any detected QTL. Two genomewide significant QTL and one suggestive QTL were detected in the genome scan. The most significant QTL was mapped to linkage group 21 and was significant at the genomewide level in both the sire and the dam-based analyses. The identified QTL can be applied in marker-assisted selection programs to improve the resistance of salmon to IPN and reduce disease-related mortality.     

The role of testosterone in aggressive and non-aggressive risk-taking in adolescent boys

While there exists increasing evidence of a relationship between testosterone (T) and risk-taking (RT), many issues remain unsolved. This paper tries to address two main-questions: (i) does T influence aggressive risk-taking (ART) and/or non-aggressive risk-taking (NART) behavior and (ii) is this relationship stable throughout age and pubertal development and how is the relationship affected by affiliations with peers that are highly involved in RT, referred to as differential association (DA)? For a sample of 301 third-grade adolescent boys (mean age 14.4 years), we assessed the relationship between serum levels of T and estradiol (E2), DA and ART/NART. Significant effects of SHBG (Beta=-0.15; p<0.029) and free testosterone (FT) (Beta=0.23; p<0.003) on NART were shown. No significant effects were found with respect to ART. Further analyses showed that the FT-NART and the FT-ART relations differed as to age but not as to pubertal development (PD) and that the relationship between FT and RT is mediated by DA as such that individuals with higher levels of FT have friends that are more involved in RT and their influence contributes to increased levels of RT. Our results indicate that hormone-related interests and predispositions may influence the development of affiliations with risk-taking peers, a factor which is crucial in understanding adolescent RT.     

Inhibition between invasives: a newly introduced predator moderates the impacts of a previously established invasive predator

1. With continued globalization, species are being transported and introduced into novel habitats at an accelerating rate. Interactions between invasive species may provide important mechanisms that moderate their impacts on native species. 2. The European green crab Carcinus maenas is an aggressive predator that was introduced to the east coast of North America in the mid-1800 s and is capable of rapid consumption of bivalve prey. A newer invasive predator, the Asian shore crab Hemigrapsus sanguineus, was first discovered on the Atlantic coast in the 1980s, and now inhabits many of the same regions as C. maenas within the Gulf of Maine. Using a series of field and laboratory investigations, we examined the consequences of interactions between these predators. 3. Density patterns of these two species at different spatial scales are consistent with negative interactions. As a result of these interactions, C. maenas alters its diet to consume fewer mussels, its preferred prey, in the presence of H. sanguineus. Decreased mussel consumption in turn leads to lower growth rates for C. maenas, with potential detrimental effects on C. maenas populations. 4. Rather than an invasional meltdown, this study demonstrates that, within the Gulf of Maine, this new invasive predator can moderate the impacts of the older invasive predator.     

Monoterpene glycosides isolated from Fadogia agrestis

Six monoterpene glycosides were isolated from Fadogia agrestis. Their structures were elucidated using a combination of mass spectroscopy, 1D- and 2D-homo- and hetero-NMR spectroscopy and chemical analysis, and established as being derivatives of 2,6-dimethyl-2(E),6(Z)-octadiene-1,8-diol containing from two to four units of rhamnopyranose and, three of them, one or two additional units of glucopyranose. In three of the compounds an acyl group of 8-hydroxy-2,6-dimethyl-2(E),6(Z)-octadienoyl was found esterifying the O-2 position of one of the units of rhamnopyranose.     

Landscape characteristics, spatial extent, and breeding bird diversity in Ohio, USA

Abstract. Avian communities are often used by ecologists as indicators of environmental decline over large spatial areas, because of the ease with which birds can be monitored by nonprofessionals and the availability of continent‐wide breeding bird data. The influence of scale on the relationship between bird diversity and the characteristics of the landscape, which can serve as proxies for decline, is receiving greater attention but is still not well understood. We combined data from the Breeding Bird Survey with landscape characteristics derived from the National Land Classification Data for Ohio, USA, to determine the effects of landscape extent on relationships between birds and landscape characteristics. These relationships were determined through previous work to be correlated with avian richness and diversity. We created areas of varying sizes using buffers around each of 58 routes, and calculated diversity for several groups of birds: all birds, five habitat guilds, and three migration guilds. The landscape extent over which landscape characteristics were considered affected the relationship between these characteristics and bird richness and diversity overall, as well as richness and diversity for several of the habitat and migratory guilds. Diversity of woodland birds, Neotropical migrants, and richness of short‐distance migrants were best explained by the landscape characteristics examined here, possibly due to a less homogeneous collection of species in the other guild groups. These results suggest that more attention is required in selecting the appropriate scale when using landscape characteristics to predict or manage avian communities, as some characteristics may be more useful for management activities over small areas versus efforts over larger areas.     

Conservation units based on mitochondrial and nuclear DNA variation among European bullhead populations (Cottus gobio L., 1758) from Flanders, Belgium

In this study, we aimed to delineateevolutionarily significant units (ESUs) andmanagement units (MUs) for the Europeanbullhead in Flanders (Belgium). Therefore, wedetermined the genetic interrelationshipsbetween 11 bullhead populations, using lengthvariation at 7 polymorphic microsatellite lociand sequence variation in the d-loop of themitochondrial DNA (mtDNA). Despite therelatively small geographical scale of ourstudy, the analysis of the d-loop sequencesshows that the Flemish bullhead populationscontain 3 haplotype groups, which can beassigned to 3 previously described EuropeanmtDNA clades. Because of the importantdifferences between these clades, they may bedefined as evolutionarily significant units,which should be managed separately. Analysis ofmicrosatellite data reveals very high degreesof isolation between populations, with theexception of 3 pairwise comparisons whichinvolved adjacent populations. Our data suggestthat the 3 haplotype groups probably qualify asESUs, as they show phylogeographicdifferentiation for mtDNA variants as well assignificant divergence of allele frequencies atnuclear loci. However, one of these units,limited to a single population, may be ofCentral European origin. All populations of theScheldt basin meet the criteria for MUrecognition, since significantly differentmicrosatellite allele frequencies as well asprivate alleles are found. In contrast, geneticdifferentiation among the 3 populations of theMeuse basin is very low.