Derivatives of aryl-4-guanidinomethylbenzoate and N-aryl-4-guanidinomethylbenzamide as new antibacterial agents: synthesis and bioactivity.

Aim: The aim of the present study was to design, synthesize, and evaluate novel antibacterial agents, derivatives of aryl-4-guanidinomethylbenzoate and N-aryl-4-guanidinomethylbenzamide.

Methods: A total of 44 derivatives of aryl-4-guanidin-omethylbenzoate (series A) and N-aryl-4-guanidinomethylbenzamide (series B) were synthesized and their antibacterial activities were assessed in vitro against a variety of Gram-positive and Gram-negative bacteria by an agar dilution method.

Results: Twelve compounds showed potent bactericidal effects against a panel of Gram-positive germs, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), vancomycin-intermediate Staphylococcus aureus (VISA), and methicillin-resistant coagulase-negative staphylococci (MRCNS), with minimum inhibitory concentrations (MIC) ranging between 0.

High-level expression and purification of Escherichia coli oligopeptidase B.

Oligopeptidase B (OpdB) of Escherichia coli, previously called protease II, has a trypsin-like specificity, cleaving peptides at lysine and arginine residues and belongs to the prolyl oligopeptidase family of new serine peptidases. In this study, we report the fusion expression of E. coli oligopeptidase B with an N-terminal histidine tag using pET28a as the expression vector.

[Preparation and spectral properties of PVP-modified CdS nanorods].

Polyvinylpyrrolidone (PVP)-modified CdS nanorods were prepared by a hydrothermal reaction of CdCl2 2.5H2O and (NH4)2S with 10 wt% ethylenediamine aqueous solution as solvent and 1.0 wt% PVP as additives.

Bactericidal and morphological effects of NE-2001, a novel synthetic agent directed against Helicobacter pylori.

The antibacterial activities of NE-2001 were tested against 24 clinical isolates of Helicobacter pylori and compared with those of amoxicillin, clarithromycin, metronidazole, and furazolidone. The MIC(50) and MIC(90) of this synthetic compound on the isolates were 8 and 16 mug/ml, respectively. This action was highly selective against Helicobacter pylori; there was a >4-fold difference between the concentration of NE-2001 required to inhibit the growth of Helicobacter pylori and that required to inhibit the growth of common aerobic and anaerobic bacteria.

The leucyl aminopeptidase from Helicobacter pylori is an allosteric enzyme.

This study describes the cloning, genetic analysis and biochemical characterization of a leucyl aminopeptidase (LAP) from Helicobacter pylori. A gene encoding LAP was cloned from H. pylori and the expressed 55 kDa protein displayed homology to aminopeptidases from Gram-negative bacteria, plants and mammals.

A specific anti-Helicobacter pylori agent NE2001: synthesis and its effect on the growth of H. pylori.

The synthesis and anti-Helicobacter pylori activity of a novel agent NE2001, 4-(4-methylbenzyl)-4'-[guanidinomethylbenzoyloxy] biphenyl-4-carboxylate hydrochloride, are described. NE2001 had a specific inhibitory effect on the growth of H. pylori preceded by the suppression DNA synthesis in the cell.

Separation and Characterization of Oligodeoxynucleotides by FPLC.

The purity of the antisense drugs synthesized by DNA synthesizer should be determined effectively. At pH 12,the oligodeoxynucleotides (ODNs) ranged from 19 bases to 21 bases can be separated successfully on the anion exchange column MONO-Q by elution with a NaCl gradient. The experiments proved that the fast protein liquid chromatography (FPLC) was a useful tool for isolation and identification of the antisense drugs.

Construction of Urokinase Mutant Glu154-mtcu-PA and Characterization of Its Properties.

The recombinant single chain urokinase-type plasminogen activator (rscu-PA) and a mutant constructed by in vitro site-specific mutagenesis of Argl54 in rscu-PA to Glul54 (Glul54-mscu-PA) were both expressed in E. coli. The expressed products were both purified to homogeneity by in vitro denaturation and renaturation, followed by Zn(2+) selective precipitation and immuno-affinity chromatography.

Cloning and Expression of the rpoH Gene from Escherichia coli and Its Product Purification.

The rpoH gene, encoding the heat shock protein transcription factor sigma(32), was obtained by PCR and cloned into plasmid pUHE with the tac promoter. Upon induction with IPTG, it directed the expression of sigma(32) tailed with six additional histidine residues at its C-terminus. The histidine-tagged sigma(32) was purified with nickel-iminodiacetic acid affinity chromatography.

The Construction of GPRP-scu-PA(144-411) cDNA and the Study of Its Properties.

A synthetic nucleic acids fragment encoding the GPRP peptides was linked with the scu-PA (144-411) cDNA at its 5' end, and was subsequently inserted into the expression vector pKK233-2 and expressed in E. coli with a level of 5% of the total bacterial proteins. The expressed product of GPRP-scu-PA (144-411) cDNA was purified by affinity chromatography.