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Bacteria Escherichia Coli (bacteria + escherichia_coli)
Selected AbstractsSynthesis, Cytotoxicity and Antibacterial Studies of p -Methoxybenzyl-Substituted and Benzyl-Substituted N-Heterocyclic Carbene,Silver ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 7 2010Siddappa Patil Abstract p -Methoxybenzyl-substituted and benzyl-substituted N-heterocyclic carbene (NHC) [(3a,c) and (6a,c)] precursors were synthesised from the reaction of 1H -imidazole (1a), 4,5-dichloro-1H -imidazole (1b), and 1H -benzimidazole (1c) with p -methoxybenzyl bromide (2) and benzyl bromide (5). These NHC precursors were then treated with silver(I) acetate to yield the NHC,silver complexes [1,3-bis(4-methoxybenzyl)imidazol-2-ylidene]silver(I) acetate (4a), [4,5-dichloro-1,3-bis(4-methoxybenzyl)imidazol-2-ylidene]silver(I) acetate (4b), [1,3-bis(4-methoxybenzyl)benzimidazol-2-ylidene]silver(I) acetate (4c), (1,3-dibenzylimidazol-2-ylidene)silver(I) acetate (7a), (1,3-dibenzyl-4,5-dichloroimidazol-2-ylidene)silver(I) acetate (7b), and (1,3-dibenzylbenzimidazol-2-ylidene)silver(I) acetate (7c), respectively. The NHC precursor 3c, four NHC,silver complexes 4c and 7a,c were characterised by single-crystal X-ray diffraction method. The preliminary antibacterial activity of all the compounds was studied against Gram-negative bacteria Escherichia coli, and Gram-positive bacteria Staphylococcus aureus using the Kirby,Bauer disk-diffusion method. Almost all the NHC,silver complexes have shown high antibacterial activity compared to the NHC precursors. In addition, the NHC,silver complexes had their cytotoxicity investigated through MTT-based preliminary in vitro testing on the Caki-1 cell lines in order to determine their IC50 values. NHC,silver complexes 4a,c and 7a,c were found to have IC50 values of 7.3 (+/,6), 12.7(+/,3), 25.2 (+/,5), 2.5 (+/,3), 10.8 (+/,4) and 12.5 (+/,4) ,M respectively on the Caki-1 cell line. [source] Comparative study on the antimicrobial activities of different sandalwood essential oils of various originFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2006Leopold Jirovetz Abstract In total, eight samples of different sandalwoods [Amyris balsamifera L., Santalum album L. and Santalum spicatum (R.Br.) A.DC.] and a mixture of , - and , -santalols, as well as eugenol as reference compound, were tested by an agar dilution and agar diffusion method for their antimicrobial activities against the yeast Candida albicans, the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The main compounds of each essential oil were investigated by gas chromatographic,spectroscopic (GC-FID and GC,MS) and ,olfactory methods to obtain information about the inßuence of these volatiles on the observed antimicrobial effects. For the santalol mixture, as well as for one S. album and one S. spicatum sample with moderate concentrations of santalols, antimicrobial activity was found against all the strains used. The A. balsamifera sample, containing only a small quantity of , -santalol and nearly no , -santalol, showed high effects only against Klebsiella pneumoniae, while against the other strains weak or no activity was observed. Therefore, santalols in medium and/or high concentrations in sandalwood oils show a significant inßuence on antimicrobial potential in such natural products. Copyright © 2006 John Wiley & Sons, Ltd. [source] Functional characterization of the NF-,B transcription factor gene REL2 from Anopheles gambiaeINSECT SCIENCE, Issue 3 2007NGO T. HOA Abstract The REL2 gene plays an important role in innate immunity against both Gram (+) and Gram (-) bacteria and malaria parasites in Anopheles gambiae, the main vector of malaria in Africa. Through alternative splicing, REL2 produces two protein products, REL2F (with a Rel-homology domain as well as an inhibitory ankyrin repeat region) and REL2S (without the ankyrin repeats). In the immune-competent cell line Sua1B from An. gambiae, REL2 has been shown to be a key regulator for cecropin A (or CEC1). The high level expression of CEC1 in Sua1B was postulated to be the result of constitutive activation of REL2F. Here we showed that REL2F is indeed processed, albeit at a low level, in the Sua1B cell line. The primary cleavage requires residue 678 (an aspartic acid). Proteolytic cleavage of REL2F can be enhanced by challenge with bacteria Escherichia coli and Bacillus subtilis, but not with fungus Beauveria bassiana. The inducible cleavage can be substantially reduced by RNA interference against PGRP-LC and CASPL1. Over-expression of REL2S or a constitutively active form of REL2F (REL2F380C or REL2F678) in An. gambiae cell line can further increase expression of CEC1 and other antimicrobial peptide genes. Over-expression of these constitutive active proteins in an immune naive cell line, MSQ43, from Anopheles stephensi, results in even more dramatic increased expression of antimicrobial peptides. [source] Mapping the peptide and protein immune response in the larvae of the fleshfly Sarcophaga bullataJOURNAL OF PEPTIDE SCIENCE, Issue 6 2008Alice Ciencialová Abstract We chose the larvae of fleshfly Sarcophaga bullata to map the peptide and protein immune response. The hemolymph of the third-instar larvae of S. bullata was used for isolation. The larvae were injected with bacterial suspension to induce an antimicrobial response. The hemolymph was separated into crude fractions, which were subdivided by RP-HPLC, gel electrophoresis, and free-flow electrophoresis. In several fractions, we determined significant antimicrobial activities against the pathogenic bacteria Escherichia coli, Staphylococcus aureus, or Pseudomonas aeruginosa. Among antimicrobially active compounds we identified dipeptide ,-alanyl- L -tyrosine, protein transferrin, and two variants of peptide sapecin. We also partially characterized two novel antimicrobially active polypeptides; odorant-binding protein 99b, and a peptide which remains unidentified. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] Transcriptional regulation of transport and utilization systems for hexuronides, hexuronates and hexonates in gamma purple bacteriaMOLECULAR MICROBIOLOGY, Issue 4 2000Dmitry A. Rodionov The comparative approach is a powerful tool for the analysis of gene regulation in bacterial genomes. It can be applied to the analysis of regulons that have been studied experimentally as well as that of regulons for which no known regulatory sites are available. It is assumed that the set of co-regulated genes and the regulatory signal itself are conserved in related genomes. Here, we use genomic comparisons to study the regulation of transport and utilization systems for sugar acids in gamma purple bacteria Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, Yersinia pestis, Erwinia chrysanthemi, Haemophilus influenzae and Vibrio cholerae. The variability of the operon structure and the location of the operator sites for the main transcription factors are demonstrated. The common metabolic map is combined with known and predicted regulatory interactions. It includes all known and predicted members of the GntR, UxuR/ExuR, KdgR, UidR and IdnR regulons. Moreover, most members of these regulons seem to be under catabolite repression mediated by CRP. The candidate UxuR/ExuR signal is proposed, the KdgR consensus is extended, and new operators for all transcription factors are identified in all studied genomes. Two new members of the KdgR regulon, a hypothetical ATP-dependent transport system OgtABCD and YjgK protein with unknown function, are detected. The former is likely to be the transport system for the products of pectin degradation, oligogalacturonides. [source] ORIGINAL ARTICLE: Isolation of Non-Activated Monocytes from Human Umbilical Cord BloodAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2010Erik Normann Problem, Methods for monocyte purification are common but few work with umbilical cord monocytes that do not activate the cell for subsequent culture analysis. Methods of study, The collection procedure avoids use of needles and procedures that variably activate blood clotting and uses a purification procedure that involves diluted Ficoll, autologous serum to remove platelets and 42% and 51% Percoll step gradients for the final purification. The resulting monocytes were stimulated with bacterial lipopolysaccharide and formalin-treated bacteria Escherichia coli and group B streptococci (GBS) to secrete TNF-, and IL-1,, measured by ELISA. Results, The purification procedure results in non-active but stimulation-competent monocytes with high yields (2.3,9 × 107 cells) and purity (from 70% to 98%). Conclusion, We describe a procedure that is easy, uses common reagents and provides a uniformly high yield and purity of non-activated fetal monocytes for studies of innate defense responses. [source] | |||||||||||||