Plant ABC proteins--a unified nomenclature and updated inventory

The ABC superfamily comprises both membrane-bound transporters and soluble proteins involved in a broad range of processes, many of which are of considerable agricultural, biotechnological and medical potential. Completion of the Arabidopsis and rice genome sequences has revealed a particularly large and diverse complement of plant ABC proteins in comparison with other organisms. Forward and reverse genetics, together with heterologous expression, have uncovered many novel roles for plant ABC proteins, but this progress has been accompanied by a confusing proliferation of names for plant ABC genes and their products. A consolidated nomenclature will provide much-needed clarity and a framework for future research.     

Synthesis of versatile thiol-reactive polymer scaffolds via RAFT polymerization

Well-defined polymer scaffolds convertible to (multi)functional polymer structures via selective and efficient modifications potentially provide an easy, versatile, and useful approach for a wide variety of applications. Considering this, a homopolymer scaffold, poly(pyridyldisulfide ethylmethacrylate) (poly(PDSM)), having pendant groups selectively reactive with thiols, was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. Soluble polymers with controlled molecular weights and narrow PDIs were generated efficiently. The versatility of the scaffold to generate random co- and ter-polymers combining multiple functionalities with controlled-composition was shown by separate and simultaneous conjugation of different mercapto-compounds, including a tripeptide in one-step. Conversion of water-insoluble scaffold to peptide-containing water-soluble copolymers was observed to yield nanometer-size particles with narrow polydispersity. The overall results suggest that the well-defined PDSM homopolymer scaffold generated via RAFT polymerization can be a versatile building block for generation of new structures having potential for drug delivery applications via a straightforward synthetic approach.     

Broad modulation of gene expression in CD4+ lymphocyte subpopulations in response to low doses of ionizing radiation

Gruel, G., Voisin, P., Vaurijoux, A., Roch-Lefèvre, S., Gré goire, E., Maltère, P., Petat, C., Gidrol, X., Voisin, P. and Roy, L. Broad Modulation of Gene Expression in CD4(+) Lymphocyte Subpopulations in Response to Low Doses of Ionizing Radiation. Radiat. Res. 170, 335-344 (2008).To compare the responses of the different lymphocyte subtypes after an exposure of whole blood to low doses of ionizing radiation, we examined variations in gene expression in different lymphocyte subpopulations using microarray technology. Blood samples from five healthy donors were independently exposed to 0 (sham irradiation), 0.05 and 0.5 Gy of ionizing radiation. Three and 24 h after exposure, CD56(+), CD4(+) and CD8(+) cells were negatively isolated. RNA from each set of experimental conditions was competitively hybridized on 25k oligonucleotide microarrays. Modifications of gene expression were measured after both intervals and in all cell types. Twenty-four hours after exposure to 0.5 Gy, we observed an induction of the expression of BAX, PCNA, GADD45, DDB2 and CDKN1A. However, the numbers of modulated genes greatly differed between cell types. In particular, 3 h after exposure to doses as low as 0.05 Gy, the number of down-modulated genes was 10 times greater for CD4(+) cells than for all other cell types. Moreover, most of these repressed genes were taking part in the cell processes of protein biosynthesis and oxidative phosphorylation. The results suggest that several biological pathways in CD4(+) cells could be sensitive to low doses of radiation. Therefore, specifically studying CD4(+) cells could help to understand the mechanisms involved in low-dose response and allow their detection.     

Confirmation of the presence and use of sandy beach surf-zones by juvenile Chinook salmon

Migration patterns and habitat use of sub-yearling Chinook salmon during initial ocean entrance is poorly understood. Twenty-five years ago, sub-yearling Chinook salmon were hypothesized to stay close to shore (<5 km). To test this hypothesis we sampled the surf-zone of a southern Oregon dissipative sandy beach throughout the summer of 2006 (06/07–09/29) using a beach seine in 1 m of water depth. We caught 48 sub-yearlings over six dates (07/22 to 09/01). Mean standard length of Chinook salmon caught in the surf-zone increased from 9.1 ± 0.6 (07/22/06) to 11.6 ± 0.7 cm (09/01/06), suggesting a mean increase of 0.6 mm in standard length (S.L.) per day. Early in the summer, smaller fish fed mostly on amphipods. Later in the summer, larger juveniles fed primarily on larval and juvenile fish. All prey items were common in the surf-zone. Juveniles appear to migrate from the estuary to the surf-zone where they feed on the local zooplankton for up to two summer months before migrating offshore.     

Discovery of GlyT1 inhibitors with improved pharmacokinetic properties

Glycine transporter 1 (GlyT1) represents a novel target for the treatment of schizophrenia via the potentiation of glutamatergic NMDA receptors. The discovery of 4,4-disubstituted piperidine inhibitors of GlyT1 which exhibit improved pharmacokinetic properties, including oral bioavailability, is discussed.     

Detailed Recombination Studies Along Chromosome 3B Provide New Insights on Crossover Distribution in Wheat (Triticum aestivum L.)

In wheat (Triticum aestivum L.), the crossover (CO) frequency increases gradually from the centromeres to the telomeres. However, little is known about the factors affecting both the distribution and the intensity of recombination along this gradient. To investigate this, we studied in detail the pattern of CO along chromosome 3B of bread wheat. A dense reference genetic map comprising 102 markers homogeneously distributed along the chromosome was compared to a physical deletion map. Most of the COs (90%) occurred in the distal subtelomeric regions that represent 40% of the chromosome. About 27% of the proximal regions surrounding the centromere showed a very weak CO frequency with only three COs found in the 752 gametes studied. Moreover, we observed a clear decrease of CO frequency on the distal region of the short arm. Finally, the intensity of interference was assessed for the first time in wheat using a Gamma model. The results showed m values of 1.2 for male recombination and 3.5 for female recombination, suggesting positive interference along wheat chromosome 3B.     

Genome scan to assess the respective role of host-plant and environmental constraints on the adaptation of a widespread insect

Background  

The evolutionary success of phytophagous insects could result from their adaptation to different host-plants. Alternatively, the diversification of widespread species might be driven by adaptation along environmental gradients. To disentangle the respective roles of host-plant versus abiotic environmental variables acting on the genome of an oligophagous insect, we performed a genome scan using 83 unlinked AFLP markers on larvae of the large pine weevil collected on two host-plants (pine and spruce) in four forestry regions across Europe.     

Synthesis and SAR of GlyT1 inhibitors derived from a series of N-((4-(morpholine-4-carbonyl)-1-(propylsulfonyl)piperidin-4-yl)methyl)benzamides

This Letter describes the synthesis and SAR, developed through an iterative analog library approach, of potent and selective non-sarcosine-derived GlyT1 inhibitors.