Search results for "Staphylococcus"
showing 10 items of 371 documents
Transmembrane beta-barrel of staphylococcal alpha-toxin forms in sensitive but not in resistant cells.
1997
Staphylococcal α-toxin is a 293-residue, single-chain polypeptide that spontaneously assembles into a heptameric pore in target cell membranes. To identify the pore-forming domain, substitution mutants have been produced in which single cysteine residues were introduced throughout the toxin molecule. By attaching the environmentally sensitive dye acrylodan to the sulfhydryl groups, the environment of individual amino acid side chains could be probed. In liposomes, a single 23-amino acid sequence (residues 118–140) was found to move from a polar to a nonpolar environment, indicating that this sequence forms the walls of the pore. However, periodicity in side chain environmental polarity coul…
Assembly of human contact phase proteins and release of bradykinin at the surface of curli-expressing Escherichia coli.
1996
Previous work has demonstrated that most strains of the human pathogen Streptococcus pyogenes bind kininogens through M protein, a fibrous surface protein and virulence determinant. Here we find that strains of several other pathogenic bacterial species, both Gram-positive and Gram-negative, isolated from patients with sepsis, also bind kininogens, especially kininogen (HK). The most pronounced interaction was seen between HK and Escherichia coli. Among clinical isolates of E. coli, the majority of the enterohaemorrhagic, enterotoxigenic, and sepsis strains, but none of the enteroinvasive and enteropathogenic strains, bound HK. Binding of HK to E. coli correlated with the expression of curl…
Characterization of PAMP/PRR interactions in European eel (Anguilla anguilla) macrophage-like primary cell cultures
2013
The eel (Anguilla anguilla) has been identified as a vulnerable species with stocks dramatically declining over the past decade. In an effort to support the species from overfishing of wild stocks increased interest in eel aquaculture has been notable. In order to expand the scarce knowledge concerning the biology of this species significant research efforts are required in several fields of biology. The development of cell culture systems to study the immune response is a key step towards an increased understanding of the immune response and to develop resources to support further study in this threatened species. Macrophages are one of the most important effector cells of the innate immun…
Dual Enzyme-Responsive Capsules of Hyaluronic Acid-block-Poly(Lactic Acid) for Sensing Bacterial Enzymes.
2015
The synthesis of novel amphiphilic hyaluronic acid (HYA) and poly(lactic acid) (PLA) block copolymers is reported as the key element of a strategy to detect the presence of pathogenic bacterial enzymes. In addition to the formation of defined HYA-block-PLA assemblies, the encapsulation of fluorescent reporter dyes and the selective enzymatic degradation of the capsules by hyaluronidase and proteinase K are studied. The synthesis of the dual enzyme-responsive HYA-b-PLA is carried out by copper-catalyzed Huisgen 1,3-dipolar cycloaddition. The resulting copolymers are assembled in water to form vesicular structures, which are characterized by scanning electron microscopy, transmission electron…
Isolation, purification and antibacterial effects of fusaproliferin produced by Fusariumsubglutinans in submerged culture.
2009
To evaluate the fusaproliferin (FUS) production, Fusariumsubglutinans ITEM 2404 was grown in a liquid medium of potato being this mycotoxin purified by high-performance liquid chromatography (HPLC) with a C18 semipreparative column using a mobile phase of acetonitrile/H(2)O using gradient conditions. The purity of the fusaproliferin was verified by analytical HPLC, ultraviolet absorbance measurements, LC/MS-MS, (1)H NMR spectroscopy. The isolated FUS was shown to be free of impurities and can be used as a standard for routine analysis. The pure fusaproliferin was utilized to study the biological activity on Escherichiacoli and Staphylococcusaureus. This study demostred that FUS not showed s…
Inhalable polymer-glycerosomes as safe and effective carriers for rifampicin delivery to the lungs
2016
Rifampicin loaded glycerosomes, vesicles composed of phospholipids, glycerol and water, were combined with trimethyl chitosan chloride (TMC) to prepare TMC-glycerosomes or, alternatively, with sodium hyaluronate (HY) to obtain HY-glycerosomes. These new hybrid nanovesicles were tested as carriers for pulmonary delivery of rifampicin. Glycerosomes without polymers were also prepared and characterized. All vesicles were similar: they were spherical, multilamellar and able to incorporate good amount of rifampicin (EE%∼55%). The addition of the polymers to the formulations allowed an increase of mean diameter. All the glycerosomes, in particular HY-glycerosomes, were able to deliver the drug to…
Microbial and chemical origins of the bactericidal activity of thermally treated yellow mustard powder toward Escherichia coli O157:H7 during dry sau…
2010
Abstract Work examines the origin of bactericidal activity in mustard flour and explores the relative contribution from starter cultures, E. coli O157:H7 itself and other sources. Bacteria can degrade naturally occurring glucosinolates in mustard and form isothiocyanates with antimicrobial activity. In the present work, 24 starter cultures (mostly from commercial mixtures) were screened for their capacity to decompose the glucosinolate, sinalbin. The most active pair, Pediococcus pentosaceus UM 121P and Staphylococcus carnosus UM 123M, were used together for the production of dry fermented sausage contaminated with E. coli O157:H7 (~ 6.5 log CFU/g). They were compared to industrial starters…
Constituents of leaves and flowers essential oils of Helichrysum pallasii (Spreng.) Ledeb. growing wild in Lebanon.
2009
The chemical compositions of the essential oils obtained from leaves and flowers of Helichrysum pallasii were analyzed by gas chromatography and gas chromatography-mass spectrometry. Among the 102 identified constituents, hexadecanoic acid (16.2%), (Z,Z)-9,12-octadecadienoic acid (6.8%), tetradecanoic acid (2.6%), and (Z)-caryophyllene (4.2%) were the main constituent of the oil from leaves, while in the oil from flowers hexadecanoic acid (14.7%), (Z,Z)-9,12-octadecadienoic acid (14.2%), (Z)-caryophyllene (3.6%), and delta-cadinene (3.1%) predominated. The oils were both characterized by sesquiterpenes (33.4% for leaves and 33.7% for flowers, respectively) and fatty acids and esters (30.3% …
Augu preparāta un antibakteriālo vielu sinerģiskā darbība
2020
Visā pasaulē arvien vairāk tiek runāts par dažādu mikroorganismu un to izraisīto infekciju ārstēšanas iespējām. Gan nozokomiālās infekcijas, gan sabiedrībā iegūtas infekcijas ir viens no lielākajiem draudiem sabiedrības veselībai. Šīs infekcijas ir viens no galvenajiem faktoriem jaunu antibakteriālo līdzekļu vai to kombināciju pētīšanai. Maģistra darba ietvaros tika izmantoti baktēriju izolāti, kuri iegūti no Latvijas Universitātes mikrobioloģijas kultūru kolekcijas. Darbā tika izmantoti divi Staphylococcus aureus celmi, meticilīna jutīgais un klīniskais celms, un 11 augu komponenšu preparāts AFI. Antibakteriālo līdzekļu efektivitāte tika pārbaudīta ar hinolonu grupas pretmikrobu līdzekli –…
Daļēji ar stronciju aizvietotu hidroksil-peroksiapatītu analītiska raksturošana un antibakteriālo īpašību izpēte
2018
Daļēji ar stronciju aizvietotu hidroksil-peroksiapatītu analītiska raksturošana un antibakteriālo īpašību izpēte. Valkovska V., darba vadītāja docente, Dr. chem. Osīte A. Maģistra darbs, 72 lappuses, 26 attēli, 15 tabulas, 126 literatūras avoti, 8 pielikumi. Latviešu valodā. Darbā ir apkopota informācija par hidroksilapatītu un hidroksil-peroksiapatītu iegūšanu, fizikālajām un ķīmiskajām īpašībām, izmantošanu, analīzes metodēm, kalcija fosfātu biomateriālu mikrobioloģiskajām īpašībām, to antibakteriālās aktivitātes un toksicitātes novērtēšanu, stabilo izotopu sastāvu bioloģiskajā apatītā. Eksperimentālajā daļā veiktas kalcija hidroksilapatīta un daļēji ar stronciju aizvietotu hidroksilapatī…