Human chromosomes 9, 12, and 15 contain the nucleation sites of stress-induced nuclear bodies

We previously reported the identification of a novel nuclear compartment detectable in heat-shocked HeLa cells that we termed stress-induced Src-activated during mitosis nuclear body (SNB). This structure is the recruitment center for heat shock factor 1 and for a number of RNA processing factors, among a subset of Serine-Arginine splicing factors. In this article, we show that stress-induced SNBs are detectable in human but not in hamster cells. By means of hamster>human cell hybrids, we have identified three human chromosomes (9, 12, and 15) that are individually able to direct the formation of stress bodies in hamster cells. Similarly to stress-induced SNB, these bodies are sites of accumulation of hnRNP A1-interacting protein and heat shock factor 1, are usually associated to nucleoli, and consist of clusters of perichromatin granules. We show that the p13-q13 region of human chromosome 9 is sufficient to direct the formation of stress bodies in hamster>human cell hybrids. Fluorescence in situ hybridization experiments demonstrate that the pericentromeric heterochromatic q12 band of chromosome 9 and the centromeric regions of chromosomes 12 and 15 colocalize with stress-induced SNBs in human cells. Our data indicate that human chromosomes 9, 12, and 15 contain the nucleation sites of stress bodies in heat-shocked HeLa cells.     

Challenges at the frontiers of structural biology

A recent meeting brought together electron microscopists, crystallographers and modellers to consider the problems facing structural biologists who wish to understand large, subcellular machines, and how the methods should be extended to achieve this goal.     

Abnormal protein patterns in blood serum and cerebrospinal fluid detected by capillary electrophoresis

Capillary zone electrophoresis and high-resolution agarose gel electrophoresis were compared to detect protein components in serum and cerebrospinal fluid of patients. Both electrophoretic methods proved to be useful for detection of protein abnormalities (e.g., mono- and oligoclonal bands) in biological fluids, but capillary electrophoresis offered several important advantages, such as sample application without preliminary concentration, lack of staining procedures, and on-line evaluation of patterns. Furthermore, capillary electrophoresis exhibits shorter analysis time and high resolution with low baseline noise. The results were proven to be powerful in diagnosis and monitoring of dyscrasias in routine laboratory practice.     

Biosynthesis of chlorosome proteins is not inhibited in acetylene-treated cultures of Chlorobium vibrioforme

The composition, abundance and apparent molecular masses of chlorosome polypeptides from Chlorobium tepidum and Chlorobium vibrioforme 8327 were compared. The most abundant, low-molecular-mass chlorosome polypeptides of both strains had similar electrophoretic mobilities and abundances, but several of the larger proteins were different in both apparent mass and abundance. Polyclonal antisera raised against recombinant chlorosome proteins of Cb. tepidum recognized the homologous proteins in Cb. vibrioforme, and a one-to-one correspondence between the chlorosome proteins of the two species was confirmed. As previously shown [Ormerod et al. (1990) J Bacteriol 172: 1352–1360], acetylene strongly suppressed the synthesis of bacteriochlorophyll c in Cb. vibrioforme strain 8327. No correlation was found between the bacteriochlorophyll c content of cells and the cellular content of chlorosome proteins. Nine of ten chlorosome proteins were detected in acetylene-treated cultures, and the chlorosome proteins were generally present in similar amounts in control and acetylene-treated cells. These results suggest that the synthesis of chlorosome proteins and the assembly of the chlorosome envelope is constitutive. It remains possible that the synthesis of bacteriochlorophyll c and its insertion into chlorosomes might be regulated by environmental parameters such as light intensity.This revised version was published online in October 2005 with corrections to the Cover Date.     

Expression and distribution of pituitary adenylate cyclase-activating peptide in human prostate and prostate cancer tissues

The therapeutic potential of the intestinotrophic mediator glucagon-like peptide-2 (1-33) [GLP-2 (1-33)] has increased interest in the pharmacokinetics of the peptide. This study was undertaken to investigate whether the primary degradation product GLP-2 (3-33) interacts with the GLP-2 receptor. Functional (cAMP) and binding in vitro studies were carried out in cells expressing the transfected human GLP-2 receptor. Furthermore, a biologic response of GLP-2 (3-33) was tested in vivo. Mice were allocated to groups treated for 10 days (twice daily) with: (1) 5 microg GLP-2 (1-33), (2) 25 microg GLP-2 (3-33), (3) 5 microg GLP-2 (1-33)+100 microg GLP-2 (3-33), or (4) 5 microg GLP-2 (1-33)+500 microg GLP-2 (3-33). The intestine was investigated for growth changes. GLP-2 (3-33) bound to the GLP-2 receptor with a binding affinity of 7.5% of that of GLP-2 (1-33). cAMP accumulation was stimulated with an efficacy of 15% and a potency more than two orders of magnitude lower than that of GLP-2 (1-33). Increasing doses of GLP-2 (3-33) (10(-7)-10(-5) M) caused a shift to the right in the dose-response curve of GLP-2 (1-33). Treatment of mice with either GLP-2 (1-33) or (3-33) induced significant growth responses in both the small and large intestines, but the response induced by GLP-2 (3-33) was much smaller. Co-administration of 500 microg of GLP-2 (3-33) and 5 microg GLP-2 (1-33) resulted in a growth response that was smaller than that of 5 microg GLP-2 (1-33) alone. Consistent with the observed in vivo activities, our functional studies and binding data indicate that GLP-2 (3-33) acts as a partial agonist with potential competitive antagonistic properties on the GLP-2 receptor.     

Toward positional cloning of Vgt1, a QTL controlling the transition from the vegetative to the reproductive phase in maize

Vgt1 (Vegetative to generative transition 1) is a quantitative trait locus (QTL) for flowering time in maize (Zea mays L.). Vgt1 was initially mapped in a ca. 5-cM interval on chromosome bin 8.05, using a set of near-isogenic lines (NILs) in the genetic background of the late dent line N28, with the earliness allele introgressed from the early variety Gaspé Flint. A new large mapping population was produced by crossing N28 and one early NIL with a ca. 6-cM long Gaspé Flint introgression at the Vgt1 region. Using PCR-based assays at markers flanking Vgt1, 69 segmental NILs homozygous for independent crossovers near the QTL were developed. When the NILs were tested in replicated field trials for days to pollen shed (DPS) and plant node number (ND), the QTL followed a Mendelian segregation. Using bulk segregant analysis and AFLP profiling, 17 AFLP markers linked to the QTL region were identified. Statistical analysis indicated a substantial coincidence of the effects of Vgt1 on both DPS and ND. Vgt1 was mapped at ca. 0.3 cM from an AFLP marker. As compared to DPS, the higher heritability of ND allowed for a more accurate assessment of the effects of Vgt1. The feasibility of the positional cloning of Vgt1 is discussed.     

Electrocatalytic oxidation of NAD(P) H at mediator-modified electrodes

A review is presented dealing with electrocatalytic NADH oxidation at mediator-modified electrodes, summarising the history of the topic, as well as the present state of the art.     

Heavy metals and arsenic uptake by wild vegetation in the Guadiamar river area after the toxic spill of the Aznalcóllar mine

On 25 April 1998, approximately 4.5 hm(3) of pyritic sludge, containing 5000 mg of As kg(-1) among other pollutants, was spilled into the Agrio and Guadiamar rivers and the surrounding agricultural areas (Aznalcóllar, Seville, Southern Spain). Many trace metals such as Pb, Cu, Zn, Cd, Tl, Sb and As reached the Do?ana National Park, the largest wetland area in Europe, affecting soils, different plant and animal species. In order to recuperate the affected lands by employing plants capable of accumulating high levels of contaminants in shoots, periodical field surveys have been made to identify the metal-tolerant species that are spontaneously growing in the polluted soils, and are able to uptake one or various of the contaminants. Among the 99 different plant species studied, Anchusa azurea, Beta vulgaris, Chamaemelum fuscatum, Convolvulus arvensis, Cynodon dactylon, Diplotaxis virgata, Erodium aethiopicum, Lavatera cretica, Malva nicaeensis, Silybum marianum and, above all, Amaranthus blitoides highlight as the most promising to be used in the remediation of the affected area.     

Free fatty acid-induced hepatic insulin resistance: a potential role for protein kinase C-delta

The mechanisms of the impairment in hepatic glucose metabolism induced by free fatty acids (FFAs) and the importance of FFA oxidation in these mechanisms remain unclear. FFA-induced peripheral insulin resistance has been linked to membrane translocation of novel protein kinase C (PKC) isoforms, but the role of PKC in hepatic insulin resistance has not been assessed. To investigate the biochemical pathways that are induced by FFA in the liver and their relation to glucose metabolism in vivo, we determined endogenous glucose production (EGP), the hepatic content of citrate (product of acetyl-CoA derived from FFA oxidation and oxaloacetate), and hepatic PKC isoform translocation after 2 and 7 h Intralipid + heparin (IH) or SAL in rats. Experiments were performed in the basal state and during hyperinsulinemic clamps (insulin infusion rate, 5 mU. kg(-1). min(-1)). IH increased EGP in the basal state (P < 0.001) and during hyperinsulinemia (P < 0.001) at 2 and 7 h. Also, 7-h infusion of IH induced resistance to the suppressive effect of insulin on EGP (P < 0.05). Glycerol infusion (resulting in plasma glycerol levels similar to IH infusion) did not have any effect on EGP. IH increased hepatic citrate content by twofold, independent of the insulin levels and the duration of IH infusion. IH induced hepatic PKC-delta translocation from the cytosolic to membrane fraction in all groups. PKC-delta translocation was greater at 7 compared with 2 h (P < 0.05). In conclusion, 1) increased FFA oxidation may contribute to the FFA-induced increase in EGP in the basal state and during hyperinsulinemia but is not associated with FFA-induced hepatic insulin resistance, and 2) the progressive insulin resistance induced by FFA in the liver is associated with a progressive increase in hepatic PKC-delta translocation.