Search results for "Escher"
showing 10 items of 728 documents
Effect of crosslinking strategy on the biological, antibacterial and physicochemical performance of hyaluronic acid and ɛ-polylysine based hydrogels
2022
The design of multifunctional hydrogels based on bioactive hyaluronic acid (HA) and antibacterial cationic polymer ε-poly-L-lysine (ε-PL) is a promising tool in tissue engineering applications. In the current study, we have designed hyaluronic acid and ε-polylysine composite hydrogel systems with antibacterial and cell attractive properties. Two distinct crosslinking approaches were used: the physical crosslinking based on electrostatic at- tractions and the chemical crosslinking of charged functional groups (-NH2 and -COOH). The impact of the crosslinking strategy on fabricated hydrogel molecular structure, swelling behavior, gel fraction, morphology, porosity, visc…
Paplašināta spektra β-laktamāzes kodējošo gēnu noteikšana Escherichia coli kultūrās, kas izolētas no mājas cūkām
2017
Darba mērķis bija izpētīt Pārtikas drošības, dzīvnieku veselības un vides zinātniskajā institūtā „BIOR” izolētas Escherichia coli kultūras, nosakot TEM, OXA, SHV, CTX-M I, CTX-M II, CTX-M IV, CMY II un DHA tipa β-laktamāzes gēnu klātbūtni baktēriju kultūru paraugos. Bakalaura darbs izstrādāts 2017. gadā zinātniskā institūta “BIOR” Dzīvnieku slimību diagnostikas laboratorijas Mikrobioloģijas nodaļā un Molekulārās bioloģijas nodaļā. Pētāmie paraugi (Escherichia coli kultūras) bija iegūti no mājas cūku (Sus scrofa domestica) aklo zarnu paraugiem 2016. un 2017. gada VPP “AgroBioRes” ietvaros. Kopā tika analizēti 68 Escherichia coli kultūru paraugi no dažādām saimniecībām. β-lactamāzeskodējošo g…
Modular organization in the reductive evolution of protein-protein interaction networks
2006
Analysis of the reduction in genome size of Buchnera aphidicola from its common ancestor E. coli shows that the organization of networks into modules is the property that seems to be directly related with the evolutionary process of genome reduction.
Unexpected Modulation of Recall B and T Cell Responses after Immunization with Rotavirus-like Particles in the Presence of LT-R192G
2010
LT-R192G, a mutant of the thermolabile enterotoxin of E. coli, is a potent adjuvant of immunization. Immune responses are generally analyzed at the end of protocols including at least 2 administrations, but rarely after a prime. To investigate this point, we compared B and T cell responses in mice after one and two intrarectal immunizations with 2/6 rotavirus-like particles (2/6-VLP) and LT-R192G. After a boost, we found, an unexpected lower B cell expansion measured by flow cytometry, despite a secondary antibody response. We then analyzed CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) and CD4(+)CD25(+)Foxp3(-) helper T cells after in vitro (re)stimulation of mesenteric lymph node cells …
Recombinant expression, in vitro refolding, and biophysical characterization of the N-terminal domain of T1R3 taste receptor
2012
Facteur d'impact (5 ans) : 1,617Notoriété à 2 ans : Acceptable (biochem.res.methods); The sweet taste receptor is a heterodimeric receptor composed of the T1R2 and T1R3 subunits, while T1R1 and T1R3 assemble to form the umami taste receptor. T1R receptors belong to the family of class C G-protein coupled receptors (GPCRs). In addition to a transmembrane heptahelical domain, class C GPCRs have a large extracellular N-terminal domain (NTD), which is the primary ligand-binding site. The T1R2 and T1R1 subunits have been shown to be responsible for ligand binding, via their NTDs. However, little is known about the contribution of T1R3-NTD to receptor functions. To enable biophysical characteriza…
Adaptation to fluctuations in temperature by nine species of bacteria
2018
Rapid environmental fluctuations are ubiquitous in the wild, yet majority of experimental studies mostly consider effects of slow fluctuations on organism. To test the evolutionary consequences of fast fluctuations, we conducted nine independent experimental evolution experiments with bacteria. Experimental conditions were same for all species, and we allowed them to evolve either in fluctuating temperature alternating rapidly between 20°C and 40°C or at constant 30°C temperature. After experimental evolution, we tested the performance of the clones in both rapid fluctuation and in constant environments (20°C, 30°C and 40°C). Results from experiments on these nine species were combined meta…
Antimicrobial Effects Of The Ethanolic Extracts And Essential Oils Of Tanacetum Vulgare L From Romania
2015
Abstract This paper investigates the antimicrobial action of the extracts and essential oil of wildgrowing Tanacetum vulgare L on: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Bacilus subtilis, using the diffusion disc method. The essential oils but also the ethanolic extracts tested exhibited moderate action on Staphilococcus aureus and Bacillus subtilis and low action on E. coli and Pseudomonas aeruginosa. The moderate antimicrobial activity is related to the amount of some chemical components of the essential oil of T. vulgare flos. Thus, this paper presents also the quantitative and qualitative analysis of the essential oils of T. vulgare harvested from two differ…
Evaluation of dermal toxicity of antibacterial cotton textile coated by sol-gel technology
2017
AbstractThis paper reports about cotton textile modification by sol-gel technology with the purpose of obtaining antibacterial properties, evaluation of antibacterial properties and dermal toxicity tests of cotton textile with Zn and Si coating. Antibacterial properties evaluation against pathogenic microorganisms Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli made using the Parallel streak method in accordance with ATCC147 standard. For more specific evaluation of the coated textile, in vitro cytotoxicity test with epidermal HaCat cells was done. It is concluded that the coatings containing Zn and Si obtained by the sol-gel technology can impart antibacterial propertie…
Combining in the melt physical and biological properties of poly(caprolactone) and chlorhexidine to obtain antimicrobial surgical monofilaments.
2012
Bacterial infections on a sutured wound represent a critical problem, and the preparation of suture threads possessing antimicrobial properties is valuable. In this work, poly(caprolactone) (PCL) monofilaments were compounded at the concentration of 1, 2 and 4 % (w/w), respectively, to the antiseptic chlorhexidine diacetate (CHX). The incorporation was carried out in the melt by a single-step methodology, i.e. “online” approach. Mechanical tests revealed that the incorporation of CHX does not significantly change tensile properties of PCL fibres as the thermal profile adopted to prepare the compounded fibres does not compromise the antibacterial activity of CHX. In fact, CHX confers to comp…
Thiosulfate Reduction in Salmonella enterica Is Driven by the Proton Motive Force
2012
ABSTRACT Thiosulfate respiration in Salmonella enterica serovar Typhimurium is catalyzed by the membrane-bound enzyme thiosulfate reductase. Experiments with quinone biosynthesis mutants show that menaquinol is the sole electron donor to thiosulfate reductase. However, the reduction of thiosulfate by menaquinol is highly endergonic under standard conditions (Δ E °′ = −328 mV). Thiosulfate reductase activity was found to depend on the proton motive force (PMF) across the cytoplasmic membrane. A structural model for thiosulfate reductase suggests that the PMF drives endergonic electron flow within the enzyme by a reverse loop mechanism. Thiosulfate reductase was able to catalyze the combined …