Crop model based QTL analysis across environments and QTL based estimation of time to floral induction and flowering in <Emphasis Type="Italic">Brassica oleracea</Emphasis>

Studying quantitative traits is complicated due to genotype by environment interactions. One strategy to overcome these difficulties is to combine quantitative trait loci (QTL) and ecophysiological models, e.g. by identifying QTLs for the response curves of adaptive traits to influential environmental factors. A B. oleracea DH-population segregating for time to flowering was cultivated at different temperature regimes. Composite interval mapping was carried out on the three parameters of a model describing time to flowering as a function of temperature, i.e. on the intercept and slope of the response of time to floral induction to temperature and on the duration from transition to flowering. The additive effects of QTLs detected for the parameters have been used to estimate time to floral induction and flowering in the B. oleracea DH-population. The combined QTL and crop model explained 66% of the phenotypic variation for time to floral induction and 56% of the phenotypic variation for time to flowering. Estimation of time to floral induction and flowering based on environment specific QTLs explained 61 and 41% of the phenotypic variation. Results suggest that flowering time can be predicted effectively by coupling QTL and crop models and that using crop modelling tools for QTL analysis increases the power of QTL detection.     

Anti-inflammatory effects of sodium butyrate on human monocytes: potent inhibition of IL-12 and up-regulation of IL-10 production.

Cytokines are critical in regulating unresponsiveness versus immunity towards enteric antigens derived from the intestinal flora and ingested food. There is increasing evidence that butyrate, a major metabolite of intestinal bacteria and crucial energy source for gut epithelial cells, also possesses anti-inflammatory properties. Its influence on cytokine production, however, is not established. Here, we report that butyrate strongly inhibits interleukin-12 (IL-12) production by suppression of both IL-12p35 and IL-12p40 mRNA accumulation, but massively enhances IL-10 secretion in Staphylococcus aureus cell-stimulated human monocytes. The effect of butyrate on IL-12 production was irreversible upon the addition of neutralizing antibodies to IL-10 or transforming growth factor b1 and of indomethacin. In anti-CD3-stimulated peripheral blood mononuclear cells, butyrate enhanced IL-10 and IL-4 secretion but reduced the release of IL-2 and interferon-g. The latter effect was in part a result of suppressed IL-12 production but also a result of inhibition of IL-12 receptor expression on T cells. These data demonstrate a novel anti-inflammatory property of butyrate that may have broad implications for the regulation of immune responses in vivo and could be exploited as new therapeutic approach in inflammatory conditions.     

Isolation and characterization of the plasma membrane from the yeast Pichia pastoris

Despite similarities of cellular membranes in all eukaryotes, every compartment displays characteristic and often unique features which are important for the functions of the specific organelles. In the present study, we biochemically characterized the plasma membrane of the methylotrophic yeast Pichia pastoris with emphasis on the lipids which form the matrix of this compartment. Prerequisite for this effort was the design of a standardized and reliable isolation protocol of the plasma membrane at high purity. Analysis of isolated plasma membrane samples from P. pastoris revealed an increase of phosphatidylserine and a decrease of phosphatidylcholine compared to bulk membranes. The amount of saturated fatty acids in the plasma membrane was higher than in total cell extracts. Ergosterol, the final product of the yeast sterol biosynthetic pathway, was found to be enriched in plasma membrane fractions, although markedly lower than in Saccharomyces cerevisiae. A further characteristic feature of the plasma membrane from P. pastoris was the enrichment of inositol phosphorylceramides over neutral sphingolipids, which accumulated in internal membranes. The detailed analysis of the P. pastoris plasma membrane is discussed in the light of cell biological features of this microorganism especially as a microbial cell factory for heterologous protein production.     

Multiple male morphs in the leaf‐footed bug Mictis longicornis (Hemiptera: Coreidae)

Species within the coreid clade (Hemiptera: Coreidae) can often be observed competing in intrasexual competitions over access to mates and territories. Coreids that partake in these competitions typically possess sexually dimorphic hind legs that are used to strike and squeeze their rivals. In addition to their weaponized legs, some coreid species also possess sexually dimorphic abdominal tubercles, which are assumed to be sexually selected weapons. Still, much remains unknown about the morphology of these structures. Here, using the species Mictis longicornis Westwood, we investigate the frequency distribution and static allometry of abdominal thickness, a measure that includes tubercle length. Furthermore, we also investigate the morphological relationship between abdominal tubercles and weaponized hind legs. We find that male abdominal thickness is best explained by a bimodal distribution, thereby describing the first observed male polymorphism in the coreid clade; a phenomenon typically associated with alternative reproductive tactics. Additionally, we find that major males are characterized primarily by having large weaponized legs and abdominal tubercles, which further suggests that abdominal tubercles are used in male–male competition.     

A low-spin iron complex in human melanoma and rat hepatoma cells and a high-spin iron(II) complex in rat hepatoma cells.

Human melanoma and rat hepatoma cells cultured in the presence of low concentrations (2.5 microM) of low-molecular-weight iron (Fe) chelates and Fe-transferrin complexes have been studied with 57Fe M?ssbauer spectroscopy. The spectra show that holoferritin is only a minor fraction of the total iron present in the cells. The major form of Fe was in a low-spin state unlike the high-spin Fe(III) found in ferritin. Only about 10% of the Fe could be attributed to ferritin. In addition, the hepatoma cells had a high-spin Fe(II) spectral component which made up about 20% of the Fe present.     

Identification of functional PDZ domain binding sites in several human proteins

TIP-15 was previously identified as a cellular protein that can bind to the C-terminal end of the HTLV-1 Tax protein via its two PDZ domains. The sequence of the N-terminal part of TIP-15 is identical to that of the synaptic protein PSD-95. Both proteins are likely to be produced from the same gene by alternative splicing. Whereas expression of the PSD-95 mRNA was detected only with brain RNAs, that of TIP-15 was detected with RNAs from thymus, brain, skeletal muscle and Jurkat cells. The TIP-15 protein exhibits an apparent molecular weight of 40 kD and is weakly expressed in T cell lines. A two-hybrid screen performed with TIP-15 as bait revealed the presence of a PDZ binding site (PDZ-BS) in the following proteins: Lysyl tRNA synthetase, 6-phosphogluconolactonase (6-GPL), Stress-activated protein kinase 3 (SAPK3), NET-1, Diacylglycerol kinase zeta, MTMR1, MCM7, and hSec8. The sequence at the C-terminal ends of these proteins matches the X-S/T-X-V-COOH consensus previously defined for PDZ-BSs, with the exception of 6-GPL and SAPK3 which include a leucine as the C-terminal residue. For Lysyl tRNA synthetase, NET1, MTMR1 and hSec8, binding to TIP-15 was confirmed by co-immunoprecipitation experiments performed with the extracts of transfected COS7 cells. These results show the existence of functional PDZ-BSs in these proteins, but future studies will be necessary to establish whether or not TIP-15 represents a physiological partner. The significance of the presence of a PDZ-BS in these various proteins is discussed with respect to their function.     

The look-ahead effect of phenotypic mutations

Background  

The evolution of complex molecular traits such as disulphide bridges often requires multiple mutations. The intermediate steps in such evolutionary trajectories are likely to be selectively neutral or deleterious. Therefore, large populations and long times may be required to evolve such traits.