The role of integration host factor In gene expression in Escherichia coli

Integration host factor is a sequence-specific, histone-like, multifunctional DNA-binding and -bending protein of Escherichia coli. The characterization and functional analysis of this protein has been done mainly in bacteriophage lambda and other mobile genetic elements. Less is known concerning the role of integration host factor (IHF) in E. coli, although it has been implicated in a number of processes in this organism including DNA replication, site-specific recombination, and gene expression. This review presents recent work which suggests that IHF alters the activity of an unusually large number of operons in E. coli. We discuss the possible physiological relevance of the involvement of IHF in gene expression and the hypothesis that IHF is a member of a class of functionally redundant proteins that participate in chromosome structure and multiple processes involving DNA.     

Cloning of cysE gene of Escherichia coli with a mini-Mu-lac containing a plasmid replicon

The restriction map of cysE gene of Escherichia coli was established after cloning a mini-Mu-lac bacteriophage containing a plasmid replicon and recloning on pBR322 vector plasmid. Enzyme assays of transformants indicated the lack of autoregulation of cysE gene.     

Modification of non-protein thiols contents in transgenic tobacco plants producing bacterial enzymes of cysteine biosynthesis pathway

Conditions of achieving the maximal accumulation of sulfhydryl metabolites in the leaves of tobacco were explored. Simultaneous production of bacterial O-acetylserine (thiol)-lyase and serine acetyltransferase resulted in the increased thiols contents as compared to single transformants and controls. However, leaf discs feeding experiments differently affected thiols concentration in different plant groups and suggested that the most promising strategy to obtain plants with a high level of non-protein thiol-containing compounds might be sulfate feeding to plants overproducing serine acetyltransferase.     

Effect of Vibrio parahaemolyticus haemolysin on human erythrocytes

Haemolysin Kanagawa, a toxin from Vibrio parahaemolyticus, is known to trigger haemolysis. Flux studies indicated that haemolysin forms a cation channel. In the present study, channel properties were elucidated by patch clamp and functional significance of ion fluxes by fluorescence-activated cell sorting (FACS) analysis. Treatment of human erythrocytes with 1 U ml-1 haemolysin within minutes induces a non-selective cation permeability. Moreover, haemolysin activates clotrimazole-sensitive K+ channels, pointing to stimulation of Ca2+-sensitive Gardos channels. Haemolysin (1 U ml-1) leads within 5 min to slight cell shrinkage, which is reversed in Ca2+-free saline. Erythrocytes treated with haemolysin (0.1 U ml-1) do not undergo significant haemolysis within the first 60 min. Replacement of extracellular Na+ with NMDG+ leads to slight cell shrinkage, which is potentiated by 0.1 U ml-1 haemolysin. According to annexin binding, treatment of erythrocytes with 0.1 U ml-1 haemolysin leads within 30 min to breakdown of phosphatidylserine asymmetry of the cell membrane, a typical feature of erythrocyte apoptosis. The annexin binding is significantly blunted at increased extracellular K+ concentrations and by K+ channel blocker clotrimazole. In conclusion, haemolysin Kanagawa induces cation permeability and activates endogenous Gardos K+ channels. Consequences include breakdown of phosphatidylserine asymmetry, which depends at least partially on cellular loss of K+.     

Autogenic training: a meta-analysis of clinical outcome studies

Autogenic training (AT) is a self-relaxation procedure by which a psychophysiological determined relaxation response is elicited. A meta-analysis was performed to evaluate the clinical effectiveness of AT. Seventy-three controlled outcome studies were found (published 1952–99). Sixty studies (35 randomized controlled trials [RCT]) qualified for inclusion in the meta-analysis. Medium-to-large effect sizes (ES) occurred for pre–post comparisons of disease-specific AT-effects, with the RCTs showing larger ES. When AT was compared to real control conditions, medium ES were found. Comparisons of AT versus other psychological treatment mostly resulted in no effects or small negative ES. This pattern of results was stable at follow-up. Unspecific AT-effects (i.e., effects on mood, cognitive performance, quality of life, and physiological variables) tended to be even larger than main effects. Separate meta-analyses for different disorders revealed a significant reduction of the heterogeneity of ES. Positive effects (medium range) of AT and of AT versus control in the meta-analysis of at least 3 studies were found for tension headache/migraine, mild-to-moderate essential hypertension, coronary heart disease, asthma bronchiale, somatoform pain disorder (unspecified type), Raynaud's disease, anxiety disorders, mild-to-moderate depression/dysthymia, and functional sleep disorders.     

A Scale-Corrected Comparison of Linkage Disequilibrium Levels between Genic and Non-Genic Regions

The understanding of non-random association between loci, termed linkage disequilibrium (LD), plays a central role in genomic research. Since causal mutations are generally not included in genomic marker data, LD between those and available markers is essential for capturing the effects of causal loci on localizing genes responsible for traits. Thus, the interpretation of association studies requires a detailed knowledge of LD patterns. It is well known that most LD measures depend on minor allele frequencies (MAF) of the considered loci and the magnitude of LD is influenced by the physical distances between loci. In the present study, a procedure to compare the LD structure between genomic regions comprising several markers each is suggested. The approach accounts for different scaling factors, namely the distribution of MAF, the distribution of pair-wise differences in MAF, and the physical extent of compared regions, reflected by the distribution of pair-wise physical distances. In the first step, genomic regions are matched based on similarity in these scaling factors. In the second step, chromosome- and genome-wide significance tests for differences in medians of LD measures in each pair are performed. The proposed framework was applied to test the hypothesis that the average LD is different in genic and non-genic regions. This was tested with a genome-wide approach with data sets for humans (Homo sapiens), a highly selected chicken line (Gallus gallus domesticus) and the model plant Arabidopsis thaliana. In all three data sets we found a significantly higher level of LD in genic regions compared to non-genic regions. About 31% more LD was detected genome-wide in genic compared to non-genic regions in Arabidopsis thaliana, followed by 13.6% in human and 6% chicken. Chromosome-wide comparison discovered significant differences on all 5 chromosomes in Arabidopsis thaliana and on one third of the human and of the chicken chromosomes.     

Comprehensive proteomic analysis of the effects of purine analogs on human Raji B-cell lymphoma

Cladribine (CdA) and fludarabine (FdAMP) are purine analogs that induce apoptosis in chronic lymphocytic leukemia and non-Hodgkin's lymphoma, but the mechanisms are undefined. The effects of CdA and fludarabine nucleoside (FdA) on the cytosolic, mitochondrial, and nuclear proteomes in human Raji lymphoma cells have been determined using two-dimensional fluorescence difference gel electrophoresis (DIGE) and mass spectrometry. Differentially abundant proteins have provided new insights into CdA- and FdA-induced apoptosis. Treatment with these purine analogs induced changes in proteins involved with intermediary metabolism, cell growth, signal transduction, protein metabolism, and regulation of nucleic acids. Differentially abundant mitochondrial 39S ribosomal protein L50, mTERF domain-containing protein 1, Chitinase-3 like 2 protein, and ubiquinone biosynthesis protein COQ9 have been identified in cells undergoing apoptosis. Up-regulation of several stress-associated proteins found in the endoplasmic reticulum (ER) including GRP78, ERp57, and ORP150 suggests that purine analog-induced apoptosis may result from ER stress and unfolded protein response. While mitochondria-dependent apoptosis has been associated with purine analog cytotoxicity, the likely involvement of the ER stress pathway in CdA- and FdA-induced apoptosis has been shown here for the first time.