Sirvi Autor "Rinken, Ago" järgi

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Aparecium tarkvara arendamine ja kasutamine retseptorsüsteemide biokeemilistes uuringutes
(Tartu Ülikool, 2019) Laasfeld, Tõnis; Kopantšuk, Sergei; Rinken, Ago; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Keemia instituut
Käesolevas töös on kirjeldatud andmetöötlusega seotud probleeme biokeemiliste katsete läbiviimisel ning nende lahendamiseks mõeldud Aparecium tarkvara eesmärke ja ülesehitust. Töös on kirjeldatud kahte praktilist rakendust, mille arendamisel ja kasutamisel on Aparecium tarkvaral andmetöötluse seisukohast määrav roll. Esimene kirjeldatud rakendus on retseptorligand interaktsioonimehhanismide uurimine muskariinse atsetüülkoliini retseptor M1 ja neuropeptiid Y Y1 retseptori näitel. Teine rakendus on meetod dopamiin D3 retseptor – ligand interaktsioonide uurimiseks. Töös kirjeldatud rakendused näitavad, et Aparecium tarkvara on kasutajasõbralik ning paindlik paljudes erinevates rakendustes kasutamiseks.
Determination of biological activity of gonadotropins hCG and FSH by Förster resonance energy transfer based biosensors
(2017) Mazina, Olga; Allikalt, Anni; Tapanainen, Juha S.; Salumets, Andres; Rinken, Ago
Determination of biological activity of gonadotropin hormones is essential in reproductive medicine and pharmaceutical manufacturing of the hormonal preparations. The aim of the study was to adopt a G-protein coupled receptor (GPCR)-mediated signal transduction pathway based assay for quantification of biological activity of gonadotropins. We focussed on studying human chorionic gonadotropin (hCG) and follicle-stimulating hormone (FSH), as these hormones are widely used in clinical practice. Receptor-specific changes in cellular cyclic adenosine monophosphate (cAMP, second messenger in GPCR signalling) were monitored by a Förster resonance energy transfer (FRET) biosensor protein TEpacVV in living cells upon activation of the relevant gonadotropin receptor. The BacMam gene delivery system was used for biosensor protein expression in target cells. In the developed assay only biologically active hormones initiated GPCR-mediated cellular signalling. High assay sensitivities were achieved for detection of hCG (limit of detection, LOD: 5 pM) and FSH (LOD: 100 pM). Even the small-scale conformational changes caused by thermal inactivation and reducing the biological activity of the hormones were registered. In conclusion, the proposed assay is suitable for quantification of biological activity of gonadotropins and is a good alternative to antibody- and animal-testing-based assays used in pharmaceutical industry and clinical research.
Ligandi ja retseptori vaheliste interaktsioonide iseloomustamine TIRF-mikroskoopia abil
(Tartu Ülikool, 2019) Kõlvart, Karl Rene; Kopantšuk, Sergei; Rinken, Ago; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Keemia instituut
Töö käigus loodi uudne TIRFM-l põhinev sidumismeetod, millega on võimalik ligandi ja retseptori vahelisi interaktsioone iseloomustada. Pinnale kinnitati viirusosakesed, mille membraanis paiknesid NPY1R-d. Kasutades fluorestsentsligande visualiseeriti sidumisprotsessi retseptoritega. Andmete põhjal leiti vastavate ligandide afiinsuskonstandid, mida võrreldi FA meetodiga saadud väärtustega. Afiinsused olid sarnases suurusjärgus ning tõestasid, et uue meetodiga on võimalik retseptori ja ligandi seostumist teatud täpsusega iseloomustada.
Zeta Potential of Extracellular Vesicles: Toward Understanding the Attributes that Determine Colloidal Stability
(ACS Publications, 2020-06-30) Midekessa, Getnet; Godakumara, Kasun; Ord, James; Viil, Janeli; Lättekivi, Freddy; Dissanayake, Keerthie; Kopanchuk, Sergei; Rinken, Ago; Aneta, Andronowska; Bhattacharjee, Sourav; Rinken, Toonika; Fazeli, Alireza
Extracellular vesicles (EVs), including exosomes and microvesicles (<200 nm), play a vital role in intercellular communication and carry a net negative surface charge under physiological conditions. Zeta potential (ZP) is a popular method to measure the surface potential of EVs, while used as an indicator of surface charge, and colloidal stability influenced by surface chemistry, bioconjugation, and the theoretical model applied. Here, we investigated the effects of such factors on ZP of well-characterized EVs derived from the human choriocarcinoma JAr cells. The EVs were suspended in phosphate-buffered saline (PBS) of various phosphate ionic concentrations (0.01, 0.1, and 1 mM), with or without detergent (Tween-20), or in the presence (10 mM) of different salts (NaCl, KCl, CaCl2, and AlCl3) and at different pH values (4, 7, and 10) while the ZP was measured. The ZP changed inversely with the buffer concentration, while Tween-20 caused a significant (p < 0.05) lowering of the ZP. Moreover, the ZP was significantly (p < 0.05) less negative in the presence of ions with higher valency (Al3+/Ca2+) than in the presence of monovalent ones (Na+/K+). Besides, the ZP of EVs became less negative at acidic pH, and vice versa. The integrated data underpins the crucial role of physicochemical attributes that influence the colloidal stability of EVs.