Control limits for accumulation of plant metabolites: brute force is no substitute for understanding.

Which factors limit metabolite accumulation in plant cells? Are theories on flux control effective at explaining the results? Many biotechnologists cling to the idea that every pathway has a rate limiting enzyme and target such enzymes first in order to modulate fluxes. This often translates into large effects on metabolite concentration, but disappointing small increases in flux. Rate limiting enzymes do exist, but are rare and quite opposite to what predicted by biochemistry.

Gold nanoparticles capped by a GC-containing peptide functionalized with an RGD motif for integrin targeting.

Gold nanoparticles were obtained by reduction of a tetrachloroaurate aqueous solution in the presence of a RGD-(GC)(2) peptide as stabilizer. As comparison, the behavior of the (GC)(2) peptide has been studied. The (GC)(2) and RGD-(GC)(2) peptides were prepared ad hoc by Fmoc synthesis.

Glutamatergic reinnervation and assembly of glutamatergic synapses in adult rat skeletal muscle occurs at cholinergic endplates.

After denervation of adult rat abdominal muscles, the postsynaptic apparatus of neuromuscular junctions (NMJs) retains its original architecture and clustering of acetylcholine receptors (AChRs). When descending fibers of the spinal cord are surgically diverted to this muscle by a nerve grafting procedure, supraspinal glutamatergic neurons can innervate muscle fibers and restore motor function; the newly formed NMJs switch from a cholinergic to a glutamatergic-type synapse. We show here that regenerating nerve endings contact the fibers in an area occupied by cholinergic endplates.

Comprehensive gene expression atlas for the Arabidopsis MAP kinase signalling pathways.

* Mitogen activated protein kinase (MAPK) pathways are signal transduction modules with layers of protein kinases having c. 120 genes in Arabidopsis, but only a few have been linked experimentally to functions. * We analysed microarray expression data for 114 MAPK signalling genes represented on the ATH1 Affymetrix arrays; determined their expression patterns during development, and in a wide range of time-course microarray experiments for their signal-dependent transcriptional regulation and their coregulation with other signalling components and transcription factors.

Polymer-supported haloarene chromium dicarbonyl isonitrile complexes: a study of their synthesis and reactivity.

Different arene Cr(CO)(3) complexes were supported on a polystyrene isonitrile resin by photochemical-promoted replacement of a chromium carbonyl ligand by the NC group. The supported complexes proved to be stable and were successfully used for further transformations. In particular, the reactivity of dichlorobenzene complexes to different nucleophiles was investigated and found to be comparable with that of the parent Cr(CO)(3) complexes.

Overexpression of nPKCdelta in BL6 murine melanoma cells enhances TGFbeta1 release into the plasma of metastasized animals.

Transforming growth factor-beta (TGFbeta) contributes to the promotion of invasion, metastasis, angiogenesis and even immunosuppression. Since overexpression of the delta isoform of protein kinase C (nPKCdelta) in BL6 murine melanoma cells (BL6T cells) increases their metastatic capacity, we investigated the possible involvement of TGFbeta1 in this process. Immunohistochemical analysis demonstrated lower levels of TGFbeta1 in BL6T lung metastases compared with BL6 lung metastases.

The minimal promoter of the human alpha 3 nicotinic receptor subunit gene. Molecular and functional characterization.

The minimal promoter of the human alpha(3) nicotinic receptor subunit gene has been mapped to a region of 60 base pairs and found to contain two Sp1 sites, one of which is essential for promoter activity. DNase footprinting has revealed the presence of another region of interaction with nuclear factors (named F2) immediately downstream of the Sp1 sites. This region has been found to be functional since it is capable of stimulating the minimal promoter.

Angiogenic capacity and lung-colonizing potential in vivo is increased in weakly metastatic B16F1 cells and decreased in highly metastatic BL6 cells by phorbol esters.

The development of tumor metastasis is a multistep process. Key aspects of this process are the interaction of tumor cells with the extracellular matrix, digestion of, and motility through the basement membrane and the induction of angiogenesis. In this study, we analysed the effects of a low dose of TPA (12-tetradecanoylphorbol-13-acetate; 0.

Increment of nonreceptor tyrosine kinase Arg RNA as evaluated by semiquantitative RT-PCR in granulocyte and macrophage-like differentiation of HL-60 cells.

The products of the human Arg gene and human, mouse, Drosophila, and nematode Abl genes characterize the Abelson family of nonreceptor tyrosine protein kinase. The Arg gene, expressed as a 12-kb transcript, codes a protein highly related to c-abl in the tyrosine kinase, SH2, and SH3 domains, and both proteins have a myristoylated isoform. The C-terminal domains of Arg and c-abl, poorly similar to each other, may account for their different functions.

Activation of protein kinase C-alpha isoform in murine melanoma cells with high metastatic potential.

Metastasis is a multistep process in which protein kinase C (PKC) appears to be significantly involved. We analysed the activity and expression of classical (alpha, beta, gamma) and novel PKC epsilon isoforms in B16-F1 and B16-BL6 melanoma cells maintained under different culture conditions in vitro. We used high and low concentrations of tyrosine and phenylalanine in different media (DMEM or RPMI 1640 respectively) that affect the metastatic potential and also the proliferative capacity of the cells.