Search results for "GRAM-NEGATIVE BACTERIA"
showing 10 items of 118 documents
Insect immunity: oral exposure to a bacterial pathogen elicits free radical response and protects from a recurring infection
2014
Background: Previous exposure to a pathogen can help organisms cope with recurring infection. This is widely recognised in vertebrates, but increasing occasions are also being reported in invertebrates where this phenomenon is referred to as immune priming. However, the mechanisms that allow acquired pathogen resistance in insects remain largely unknown. Results: We studied the priming of bacterial resi stance in the larvae of the tiger moth, Parasemia plantaginis using two gram-negative bacteria, a pathogenic Serratia marcescens and a non-pathogenic control, Escherichia coli. Asublethaloraldoseof S. marcescens provided the larvae with effective protection against an otherwise lethal septic…
Microorganism adhesion experimental study using silicon dioxide
2018
AbstractIn this study, yeast, Gram positive and Gram negative bacteria were attached to silicon dioxide microparticles or silica in order to measure their absorbance, also known as physical absorption of light, changes using spectrophotometry. The goal of the study was to determine if spectrophotometry is an effective way to distinguish microorganisms and if microorganisms have an affinity for silicon dioxide since it is a suitable material for the production of prostheses. The experiment was done by examining the light absorption properties of yeast, Gram positive and Gram negative bacteria in a spectrophotometer with and without silicon dioxide microparticles. During the experiment there …
Chemical composition and biological activity of Salvia verbenaca essential oil
2011
Salvia verbenaca L. (syn. S. minore) is a perennial herb known in the traditional medicine of Sicily as “spaccapetri” and is used to resolve cases of kidney stones, chewing the fresh leaves or in decoction. The chemical composition of the essential oil obtained from aerial parts of S. verbenaca collected in Piano Battaglia (Sicily) on July 2009, was analyzed by GC and GC-MS. The oil was strongly characterized by fatty acids (39.5%) and carbonylic compounds (21.2%), with hexadecanoic acid (23.1%), ( Z)-9-octadecenoic acid (11.1%) and benzaldehyde (7.3%) as the main constituents. The in vitro activity of the essential oil against some microorganisms in comparison with chloramphenicol by the …
Enhanced Efficacy and Broadening of Antibacterial Action of Drugs via the Use of Capped Mesoporous Nanoparticles
2013
[EN] A novel nanodevice consisting of mesoporous nanoparticles loaded with vancomycin and capped with epsilon-poly-L-lysine (epsilon-PL) was prepared and its interaction with different Gram-negative bacteria studied. A remarkable improvement in the efficacy of the antimicrobial drug epsilon-PL and a broadening of the antimicrobial spectrum of vancomycin is demonstrated.
2,6-Disubstituted imidazo[2,1-b][1,3,4]thiadiazole derivatives as potent staphylococcal biofilm inhibitors.
2019
Abstract A class of 36 new 2-(6-phenylimidazo[2,-1-b][1,3,4]thiadiazol-2-yl)-1H-indoles was efficiently synthesized and evaluated for their anti-biofilm properties against the Gram-positive bacterial reference strains Staphylococcus aureus ATCC 25923, S. aureus ATCC 6538 and Staphylococcus epidermidis ATCC 12228, and the Gram-negative strains Pseudomonas aeruginosa ATCC 15442 and Escherichia coli ATCC 25922. Many of these new compounds, were able to inhibit biofilm formation of the tested staphylococcal strains showing BIC50 lower than 10 μg/ml. In particular, derivatives 9c and 9h showed remarkable anti-biofilm activity against S. aureus ATCC 25923 with BIC50 values of 0.5 and 0.8 μg/ml, r…
The potential of antimicrobial peptides isolated from freshwater crayfish species in new drug development: A review
2021
Abstract The much-publicised increased resistance of pathogenic bacteria to conventional antibiotics has focused research effort on the characterization of new antimicrobial drugs. In this context, antimicrobial peptides (AMPs) extracted from animals are considered a promising alternative to conventional antibiotics. In recent years, freshwater crayfish species have emerged as an important source of bioactive compounds. In fact, these invertebrates rely on an innate immune system based on cellular responses and on the production of important effectors in the haemolymph, such as AMPs, which are produced and stored in granules in haemocytes and released after stimulation. These effectors are …
Endotoxins in ophthalmic viscosurgical devices.
2003
Purpose To measure the endotoxin concentration (EC) of 25 commercially available, hyaluronic acid- and hydroxypropylmethylcellulose-based (HPMC) ophthalmic viscosurgical devices (OVDs). Methods The in vitro Limulus amebocyte lysate (LAL) assay, which indicates the presence of endotoxins originating from gram-negative bacteria, was used to determine the EC. The procedure was performed according to the European Pharmacopoeia/USP. EC including duplicate determinations, negative controls, dilution series with control standard endotoxin, dilution series with sample extract and positive sample control. Results 16 OVDs (Amvisc®, Amvisc® Plus, Biolon®, Coatel®, Healon®, Healon® GV, Healon®5, HPMC O…
Chemical Composition of Two Different Lavender Essential Oils and Their Effect on Facial Skin Microbiota
2019
Lavender oil is one of the most valuable aromatherapy oils, its anti-bacterial and anti-fungal activities can be explained by main components such as linalool, linalyl acetate, lavandulol, geraniol, or eucalyptol. The aim of the study was to assess the anti-microbial effects of two different lavender oils on a mixed microbiota from facial skin. The commercial lavender oil and essential lavender oil from the Crimean Peninsula, whose chemical composition and activity are yet to be published, were used. Both oils were analysed by gas chromatography coupled to mass spectrometry. The composition and properties of studied oils were significantly different. The commercial ETJA lavender oil contain…
Identification from a Positional Scanning Peptoid Library of in Vivo Active Compounds That Neutralize Bacterial Endotoxins
2005
4 pages, 3 figures, 1 table.-- PMID: 15715495 [PubMed].-- Printed version published Feb 24, 2005.-- Supporting information available at: http://pubs.acs.org/doi/suppl/10.1021/jm040834i
Comparison of two methods skipping cell lysis and protein extraction for identification of bacteria from blood cultures by matrix-assisted laser deso…
2019
ABSTRACT Objective Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) is widely used for fast identification of bacteria from blood cultures (BC). We compared the performance of two procedures, one including a pre-enrichment step in brain heart infusion and the other a direct method using vacutainer separator gel tubes (DI), for identification of bacteria from blood cultures by MALDI-TOF MS. Material and methods We first prepared a training set of 20 simulated bacteremia specimens, including 10 Gram-negative and 10 Gram-positive species. A total of 145 non-consecutive BCs flagged as positive (68 Gram-negative rods, and 77 Gram-positive cocci) were pr…