The genome of the mesopolyploid crop species Brassica rapa

We report the annotation and analysis of the draft genome sequence of Brassica rapa accession Chiifu-401-42, a Chinese cabbage. We modeled 41,174 protein coding genes in the B. rapa genome, which has undergone genome triplication. We used Arabidopsis thaliana as an outgroup for investigating the consequences of genome triplication, such as structural and functional evolution. The extent of gene loss (fractionation) among triplicated genome segments varies, with one of the three copies consistently retaining a disproportionately large fraction of the genes expected to have been present in its ancestor. Variation in the number of members of gene families present in the genome may contribute to the remarkable morphological plasticity of Brassica species. The B. rapa genome sequence provides an important resource for studying the evolution of polyploid genomes and underpins the genetic improvement of Brassica oil and vegetable crops.     

A mutation of human cytochrome c enhances the intrinsic apoptotic pathway but causes only thrombocytopenia

We report the first identified mutation in the gene encoding human cytochrome c (CYCS). Glycine 41, invariant throughout eukaryotes, is substituted by serine in a family with autosomal dominant thrombocytopenia caused by dysregulated platelet formation. The mutation yields a cytochrome c variant with enhanced apoptotic activity in vitro. Notably, the family has no other phenotypic indication of abnormal apoptosis, implying that cytochrome c activity is not a critical regulator of most physiological apoptosis.     

Structural,VAR and BVAR models of exchange rate determination: A comparison of their forecasting performance

This paper compares the out-of-sample forecasting accuracy of a wide class of structural, BVAR and VAR models for major sterling exchange rates over different forecast horizons. As representative structural models we employ a portfolio balance model and a modified uncovered interest parity model, with the latter producing the more accurate forecasts. Proper attention to the long-run properties and the short-run dynamics of structural models can improve on the forecasting performance of the random walk model. The structural model shows substantial improvement in medium-term forecasting accuracy, whereas the BVAR model is the more accurate in the short term. BVAR and VAR models in levels strongly out predict these models formulated in difference form at all forecast horizons.     

Macrophage binding of Staphylococcus albus is blocked by anti I-region alloantibody

Cell surface interactions involving carbohydrate may be important in immune recognition. Previous work from this laboratory has demonstrated the presence of 'lectin-like' receptors on mouse peritoneal macrophages that bind bacteria by means of their cell wall sugars. Others have shown that Ia molecules can bind antigen at specific sites which may be involved in presenting antigen to the immune system and recent work has shown that these molecules can carry carbohydrate determinants. It has also been found that human Ia molecules can bind to carbohydrates. As cell surface carbohydrate recognition mechanisms have been implicated in other immune interactions sugar-specific receptors may have a function in self--non-self recognition. We show here that the binding of the bacterium Staphylococcus albus to mouse peritoneal macrophages was inhibited by various conventional and monoclonal antibodies to Ia antigens suggesting that an I-region gene product may be associated with the binding of unopsonized bacteria.     

Influence of substance P and fragments on passive avoidance behavior

Summary N-terminal and C-terminal fragments of substance P (SP) have been shown to exert opposite effects on antinociception, grooming and fighting in mice. The present experiments explored whether these findings could be generalized to passive avoidance behavior. Substance P (SP-(1-11)) and the c-terminal, fragment pyroglutamyl-SP-(7-11) attenuated passive avoidance behavior when picogram amounts were injected into the nucleus accumbens. In contrast, the N-terminal fragment, SP-(1-7) had an opposite effect and facilitated passive avoidance behavior.