Potent antimicrobial activity of 3-(4,5-diaryl-1H-imidazol-2-yl)-1H-indole derivatives against methicillin-resistant Staphylococcus aureus.

A new series of antimicrobial derivatives [3-(4,5-diaryl-1H-imidazol-2-yl)-1H-indole)] have been synthesized with potent activity against strains of Staphylococcus aureus, including methicillin-resistant strains (MRSA). Compound 17 [3-(4,5-bis(4-fluorophenyl)-1H-imidazol-2-yl)-5-bromo-1H-indole], the most active derivative was shown to inhibit the growth of all Gram-positive strains tested, including vancomycin resistant Enterococcus faecalis and Enterococcus faecium with no activity against Gram-negative bacteria.

A novel small molecule with potent anticancer activity inhibits cell growth by modulating intracellular labile zinc homeostasis.

ML-133 is a novel small molecule with potent antiproliferative activity, as shown in cancer cell lines and in a human colon tumor xenograft model. ML-133 reduces the concentration of intracellular labile zinc in HT-29 colon cancer cells, leading to induction of the Krüppel-like factor 4 transcription factor. Krüppel-like factor 4 displaces the positive regulator SP1 from the cyclin D1 promoter, thereby negatively regulating the expression of cyclin D1 and promoting the G(1)-S phase arrest of cell proliferation.

Liposome formulation of a novel hydrophobic aryl-imidazole compound for anti-cancer therapy.

Purpose: A cholesterol-free liposome formulation formed from mixtures of egg phosphatidylcholine (ePC) and poly (ethylene glycol) conjugated distearoylphosphatidylethanolamine (DSPE-PEG 2000) was optimized and evaluated for delivery of a novel anti-cancer agent ML220 (2-(5-bromo-1H-indol-3-yl)-1H-phenanthro [9,10-d] imidazole).

Results And Discussion: ML220 is highly lipophilic with a water solubility of 0.14 mug/ml and calculated log P of 5.

Adhesion and virulence properties of epidemic Canadian methicillin-resistant Staphylococcus aureus strain 1: identification of novel adhesion functions associated with plasmin-sensitive surface protein.

Epidemic Canadian methicillin-resistant Staphylococcus aureus strain 1 (CMRSA-1) comprises related subtypes that differ in phenotype and prevalence, with subtypes 1A, 1B, and 1D representing 1%, 71%, and 18%, respectively, of total CMRSA-1 isolates. The predominant CMRSA-1B subtype possesses a variant of the staphylococcal cassette chromosome mec, harboring pls, which encodes plasmin-sensitive surface protein (Pls). CMRSA-1B cells that express Pls exhibited poor adhesion to keratinocyte extracellular matrix.

Deoxyguanosine blocks allograft rejection of thymic epithelium but not lymphocyte infiltration and recognition.

Embryonic thymic lobes cultured in vitro in the presence of deoxyguanosine (dGuo) are accepted in fully mismatched recipients. The proposed explanation for this finding was the depletion of hematopoietic cells induced by the treatment associated with poor immunogenicity of thymic epithelium. We have recently demonstrated that embryonic tissues obtained at stages prior to hematopoietic colonization are nevertheless rejectable.

Embryonic thymic epithelium naturally devoid of APCs is acutely rejected in the absence of indirect recognition.

Transplants of tissues depleted of passenger leukocytes are upon in vitro culture usually accepted in allogeneic recipients. Accordingly, fully allogeneic embryonic thymic epithelium was suggested to be poorly immunogenic. However, this tissue is capable of inducing donor-specific tolerance to peripheral tissues, when restoring T cell development in nude mice, through the production of regulatory cells.

Variance in fibronectin binding and fnb locus polymorphisms in Staphylococcus aureus: identification of antigenic variation in a fibronectin binding protein adhesin of the epidemic CMRSA-1 strain of methicillin-resistant S. aureus.

The fnbA and fnbB genes of Staphylococcus aureus 8325-4 encode fibronectin (Fn) binding proteins FnBPA and FnBPB, which promote adherence to host tissues. Each adhesin contains three copies of a repeated D motif that binds Fn and is a target for vaccine development. In this study, we assess variability within the Fn-binding domain of the FnBP adhesins and evaluate factors that promote variance in Fn binding among clinical isolates.

Enterohemorrhagic Escherichia coli induces apoptosis which augments bacterial binding and phosphatidylethanolamine exposure on the plasma membrane outer leaflet.

Enterohemorrhagic Escherichia coli (EHEC) is a gastrointestinal pathogen that causes watery diarrhea and hemorrhagic colitis and can lead to serious and even fatal complications such as hemolytic uremic syndrome. We investigated the ability of EHEC to kill host cells using three human epithelial cell lines. Analysis of phosphatidylserine expression, internucleosomal cleavage of host cell DNA and morphological changes detected by electron microscopy changes revealed evidence of apoptotic cell death.

Synthetic peptide immunogens elicit polyclonal and monoclonal antibodies specific for linear epitopes in the D motifs of Staphylococcus aureus fibronectin-binding protein, which are composed of amino acids that are essential for fibronectin binding.

A fibronectin (Fn)-binding adhesin of Staphylococcus aureus contains three tandem 37- or 38-amino-acid motifs (D1, D2, and D3), which function to bind Fn. Plasma from patients with S. aureus infections contain antibodies that preferentially recognize ligand induced binding sites in the D motifs and do not inhibit Fn binding (F.

Phosphatidylethanolamine recognition promotes enteropathogenic E. coli and enterohemorrhagic E. coli host cell attachment.

Using both solid phase and liposome aggregation assays, we screened a variety of glycolipids and phospholipids and found that EHEC and EPEC bind specifically and in a dose-dependent manner to PE. This binding was consistently observed whether the lipid was immobilized on a thin layer chromatography plate, in a microtitre well or incorporated into a unilamellar vesicle suspended in aqueous solution. There was no evidence of binding to other phospholipids such as phosphatidylcholine (PC) or phosphatidylserine (PS).

Characterization of an acidic-pH-inducible stress protein (hsp70), a putative sulfatide binding adhesin, from Helicobacter pylori.

The in vitro glycolipid binding specificity of the gastric pathogen Helicobacter pylori is altered to include sulfated glycolipids (sulfatides) following brief exposure of the organism to acid pH typical of the stomach. This change is prevented by anti-hsp70 antibodies, suggesting that hsp70 may be a stress-induced surface adhesin, mediating sulfatide recognition. To facilitate investigation of the role of hsp70 in attachment, we have cloned and sequenced the H.

Inhibition of Helicobacter pylori and Helicobacter mustelae binding to lipid receptors by bovine colostrum.

Helicobacter pylori, the etiologic agent of chronic-active gastritis and duodenal ulcers in humans, and Helicobacter mustelae, a gastric pathogen in ferrets, bind to phosphatidylethanolamine (PE), a constituent of host gastric mucosal cells, and to gangliotetraosylceramide (Gg4) and gangliotriaosylceramide (Gg3). The effect of a bovine colostrum concentrate (BCC) on the interaction of H. pylori and H.

Characterization of prosomes in human lymphocyte subpopulations and their presence as surface antigens.

Prosomes, also called "multicatalytic proteinase" (MCP) or "proteasomes," are a new type of ubiquitous RNP particle present in some archeobacteria and in all eukaryotic cells tested from yeast to human. They were discovered as subcomplexes of untranslated messenger-ribonucleoproteins (mRNP) and later found to have a MCP activity putatively involved in antigen processing. Being composed of variable sets of characteristic proteins and associating small RNAs (pRNA), families of individual "mosaic" prosome particles seem to characterize the differentiation type and physiological state of individual cells and tissues.

Acidic pH changes receptor binding specificity of Helicobacter pylori: a binary adhesion model in which surface heat shock (stress) proteins mediate sulfatide recognition in gastric colonization.

The gastric pathogen helicobacter pylori is one of a number of bacteria which bind specifically to gangliotetraosylceramide, gangliotriaosylceramide, and phosphatidylethanolamine in vitro at neutral pH. Since this organism encounters an acid pH during initial infection of the stomach, we have monitored the effect of pH on receptor binding specificity and found induction of specific binding to sulfoglycolipids (sulfatide) following brief treatment at low pH. We have previously shown that heat shock proteins (hsps) bind to sulfatide, and the suspicion that this was a stress-induced response is supported by the fact that a similar change in H.

Comparison of Helicobacter mustelae and Helicobacter pylori adhesion to eukaryotic cells in vitro.

Background & Aims: Bacterial adhesion to mucosal surfaces is an important pathogenic mechanism for Helicobacter-induced gastritis. The aims of this study were to compare binding of selected Helicobacter mustelae and Helicobacter pylori strains to lipids extracted from HEp-2, Chinese hamster ovary, human embryonic lung cells, and ferret gastrointestinal tissues as well as to intact tissue culture cells and to analyze the fatty acids of the receptor.

Methods: Thin-layer chromatography overlay binding and a receptor-based immunoassay detected adhesion of bacteria to commercial lipids and to individual species within the lipid extracts.

Salmonella typhimurium gyrA mutations associated with fluoroquinolone resistance.

Spontaneous quinolone-resistant mutants obtained from Salmonella typhimurium Su694 were screened for mutations by direct DNA sequencing of an amplified PCR gyrA fragment. Substitutions Ser-83-->Phe (Ser83Phe), Ser83Tyr, Asp87Tyr, and Asp87Asn and double mutation Ala67Pro-Gly81Ser, which resulted in decreased sensitivities to ciprofloxacin, enoxacin, pefloxacin, norfloxacin, ofloxacin, and nalidixic acid, were found. The levels of resistance to quinolones for each mutant were determined.

Cytolocation of prosome antigens on intermediate filament subnetworks of cytokeratin, vimentin and desmin type.

Analysis by double-label indirect immunofluorescence of PtK1 and HeLa cells had previously demonstrated that prosome* antigens form networks that superimpose on those of the intermediate filaments of the cytokeratin type. We show here that in PtK1 cells various prosomal antigens also reside to a variable extent on intermediate filaments subnetworks of the vimentin type. In proliferating human fibroblasts the prosome and vimentin networks were found to coincide, while in proliferating myoblasts of the C2.

Universal method for the facile production of glycolipid/lipid matrices for the affinity purification of binding ligands.

Glycolipid recognition is a common motif in cellular physiology and bacterial pathogenesis. Such protein/lipid interactions are most conveniently demonstrated by the thin-layer chromatogram overlay. We have designed a simple affinity matrix for the purification of such glycolipid (or lipid) binding ligands based on the same principle, i.

Therapeutics used to alleviate peptic ulcers inhibit H. pylori receptor binding in vitro.

Treatment with bismuth-containing remedies has been long associated with the alleviation of minor gastric ailments. Bismuth salts have a potent antimicrobial activity, and are part of the current standard regime used to treat Helicobacter pylori infection. H.

Silencer and enhancer elements located at the 3'-side of the chicken and duck alpha-globin-encoding gene domains.

Enhancer activities have been observed in DNA fragments up to 1.36 kb long located on the 3'-side of the cluster of the three alpha-type globin-encoding genes in duck [Kretsovali et al., C.

Helicobacter mustelae and Helicobacter pylori bind to common lipid receptors in vitro.

Helicobacter pylori is a recently recognized human pathogen causing chronic-active gastritis in association with duodenal ulcers and gastric cancer. Helicobacter mustelae is a closely related bacterium with similar biochemical and morphologic characteristics. H.

Receptor affinity purification of a lipid-binding adhesin from Helicobacter pylori.

Our previous work has shown that Helicobacter pylori specifically recognizes gangliotetraosylceramide, gangliotriaosylceramide, and phosphatidylethanolamine in vitro. This binding specificity is shared by exoenzyme S from Pseudomonas aeruginosa, and monoclonal antibodies against this adhesin prevent the attachment of H. pylori to its lipid receptors.

Comparison of Helicobacter pylori and attaching-effacing Escherichia coli adhesion to eukaryotic cells.

Adhesion of Helicobacter pylori was reported previously to be morphologically identical to "attaching and effacing" Escherichia coli. Therefore, the aim of the present study was to define the adhesion phenotype of H. pylori LC-11 to HEp-2, KATO-III, HEL, and CHO tissue culture cells.

Patterns of cytodistribution of prosomal antigens on the vimentin and cytokeratin networks of monkey kidney cells.

Prosomes were found as mRNA-associated ribonucleoprotein particles (RNP) and cofactors of untranslated (ribosome-) free mRNP. Previous data have shown the presence of prosomal networks in the cytoplasm of PtK1 and HeLa cells and their superposition onto the intermediate filaments (IF) of cytokeratin type but little if any of vimentin type. Here it is shown that in LLC-MK2 cells various prosomal antigens are present on both, vimentin and cytokeratin networks, individual prosomal antigens superposing to variable degrees onto the IF subnetworks.

Preliminary characterization of a nuclear factor interacting with the silencer element at the 3'-side of the chicken alpha-globin gene domain.

A silencer element has been identified previously on the 3'-side of the chicken alpha-globin genes placed next to the major enhancer in this domain (Recillas Targa et al., unpublished). Deletion fragments of this negative element show the requirement of the entire DNA segment for maximum silencing activity.