ABSTRACT
In this benchmark study, 26 investigators were asked to characterize the kinetics and affinities of 10 sulfonamide inhibitors binding to the enzyme carbonic anhydrase II using Biacore optical biosensors. A majority of the participants collected data that could be fit to a 1:1 interaction model, but a subset of the data sets obtained from some instruments were of poor quality. The experimental errors in the k(a), k(d), and K(D) parameters determined for each of the compounds averaged 34, 24, and 37%, respectively. As expected, the greatest variation in the reported constants was observed for compounds with exceptionally weak affinity and/or fast association rates. The binding constants determined using the biosensor correlated well with solution-based titration calorimetry measurements. The results of this study provide insight into the challenges, as well as the level of experimental variation, that one would expect to observe when using Biacore technology for small molecule analyses.
Subject(s)
Carbonic Anhydrase II/chemistry , Carbonic Anhydrase II/metabolism , Carbonic Anhydrase Inhibitors/metabolism , Sulfonamides/antagonists & inhibitors , Biosensing Techniques , Calorimetry , Carbonic Anhydrase Inhibitors/classification , Observer Variation , Protein Binding , Research Personnel , Sulfonamides/classification , Surface Plasmon Resonance/instrumentation , Surface Plasmon Resonance/standardsABSTRACT
Colonisation and remaining of microorganism on mucus membrane of microorganism is tightly connected with adhesion mechanisms and determine the first step of physiological settlement of the organism or the first stage of clinically demonstrated infection. In Klebsiella rods there are known three types of fimbrial adhesins (type 1, 3 and KPF-28) and non-fimbrial adhesin CF29K. It is stated that Klebsiella strains adhesions are responsible for their adherence to the epithelial cells of both respiratory and urinary tracts and to intestine epithelium. The in vitro research affirmed Klebsiella rods adherence to protein matrix. The aim of our work was the establishment of character, receptor specificity and the appearance frequency of P-like called adhesin. The frequency of expression of P-like adhesin was estimated among 380 isolated from the patients strains on the basis of agglutinating methods. The amorphic character of P-like adhesin was proved using electron microscopy method. The isolation and purification of P-like protein with a help of affinity chromatography enabled to estimate the receptor specificity of the adhesin. The receptor specificity was established as similar to E.coli PapG adhesin.
Subject(s)
Adhesins, Bacterial/physiology , Klebsiella/pathogenicity , Adhesins, Bacterial/isolation & purification , Bacterial Adhesion , Humans , In Vitro Techniques , Klebsiella/isolation & purification , Microscopy, Electron , Species SpecificityABSTRACT
Gram negative Klebsiella bacilli present many pathogenic properties, which determine their ability to survive and rapid spreading in hospital environment. There are many factors responsible for the pathogenicity of Klebsiella strains: capsule, fimbriae, nonfimbrial adhesins, lipopolysaccharide of the cell wall and extracellular secreted exotoxins. Klebsiella strains are etiological agents of different nosocomial infections but also colonized gastrointestinal and respiratory tracts. The aim of our work were adhesive properties and antibiotic resistance of Klebsiella strains isolated from stool of hospitalized children, according to source of potential nosocomial infections--100 Klebsiella strains from Wroclaw and 76 strains from Opole, isolated in cases of diarrhea. The resistance of this strains to different group of antibiotics, the expression of ESBL enzymes, the activity in hemagglutination and their ability to adherence to different cell lines were tested. The highest resistance of all strains to aminopenicillins was observed. The production of ESBL was highest in strains from Opole (51% strains) then in Wroclaw (9%). In both hospital units, ESBL+ strains were resistant to aminoglicosides and cotrimoxazol but sensitive to ciprofloxacine. Using hemagglutination method the types of fimbriae were defined. Above 90% investigated Klebsiella strains showed the presence of fimbriae (in Wroclaw more strains simultaneously expressed fimbriae type 1 and 3, in Opole mainly fimbriae type 3). Over 70% strains demonstrated the high level of adherence to cell lines. Only several strains showed the low level or the lack of adhesion. These results suggested that among Klebsiella strains in gastrointestinal tract were presented multiresistant strains with high ability to adherence, which may be potential source of nosocomial infections.
