CONTENTS & ABSTRACTS
InEnglish. Summaries in Estonian
Proceedings of the Estonian Academy of Sciences.
Chemistry
Volume 53 No. 4December 2004
Modulationof adenylate cyclase activity in rat striatal membranes by adenosine A2Areceptors; 153–164
Argo Vonk, Ain Uustare, and Ago Rinken
Abstract. Possibilities of characterizing adenosine A2A receptordependent signal transduction in rat striatal membranes by activation ofadenylate cyclase were studied. By optimization of membrane preparation methodsand the composition of the incubation buffer, an up to 10-fold increase incyclic AMP (cAMP) accumulation was achieved in response to the binding of A2A-specificagonist CGS
21680. The best response was achieved in the crude striatalhomogenate in the buffer where Na+ and K+ were omittedand then the potency of CGS 21680 was characterized by EC50 = 0.5 ± 0.2 mM. Thepresence of at least 1 mM Mg2+ was required to achieve themaximal specific AC activation, but at higher concentrations magnesiumincreased the non-specific cAMP accumulation and decreased thereceptor-mediated effects. The antagonist of A2A receptors,ZM 241385, had no effect on the basal activity of adenylate cyclase instriatal homogenate, but inhibited the CGS 21680-dependent activation withaffinity that was in agreement with the binding affinity of this antagonist toA2A receptors.
Key words: adenosine A2A receptor,CGS 21680, ZM 241385, adenylate cyclase, rat striatum.
Purificationof amine oxidase from Pisum sativum for the construction of aminebiosensors; 165–173
Andero Vaarik and Toonika Rinken
Abstract. Copper-containing amine oxidase was purified from the extractof pea seedlings (Pisum sativum) for a possible application as abioselective compound of amine biosensors. The specific activity of thepurified enzyme at different purification steps was characterized with the helpof a Clark-type oxygen sensor by measuring the dissolved oxygen consumptionduring the oxidation of amine compounds. This sensing system was characterizedwith a steady-state output parameter calculated on the basis of the dynamicmodel of biosensors. Among the studied amine compounds pea seedlings amineoxidase (PSAO) was found to have the highest catalysing activity forcadaverine. The three-step purification procedure of PSAO revealed 35-foldpurification and an enzyme preparation ready for application in biosensors.
Key words: pea seedlings amine oxidase, purification, catalytic activity.
Comparative chemical composition of theessential oil of Mentha ´ piperita L.from various geographical sources; 174–181
Anne Orav, Ain Raal, andElmar Arak
Abstract. Variations in the essential oil composition of Mentha ´ piperita L.,cultivated in different European countries, were determined. The oils wereobtained in yields of 0.8–3.3% from dried samples. A total of 46 componentswere identified, representing over 90% of the total yield of oil. The principalcomponents in the oils of peppermint were menthone (11.2–45.6%), menthol(1.5–39.5%), isomenthone (1.3–15.5%), menthyl acetate (0.3–9.2%), piperitone(0.8–5.9%), pulegone (0.1–13.0), 1,8-cineole (0.4–6.0%), limonene (1.0–5.9%),and trans-sabinene hydrate (traces – 6.2%). The ratio between mentholand menthone varied from 0.04 to 2.8 and between 1,8-cineole and limonene from0.3 to 5.0. Menthol was predominant (37–40%) in the oils from Greece andHungary. Russian peppermint oil contained only 1.5% menthol, but was rich inmenthone (38.2%), isomenthone (15.5%), and pulegone (13.0%). Menthone(37.9–39.5%) and menthol (31.6 – 35.8%) were found in high concentrations inEstonian peppermint oil.
Key words: Mentha ´ piperita L., Labiatae,peppermint, essential oil, menthone, menthol, menthyl acetate.
Heavymetals in roadside soils; 182–200
Maire-Liis Hääl, Helvi Hödrejärv, andHarri Rõuk
Abstract. Strong correlations were found between traffic volume andheavy metals in the roadside soil, reflecting the vehicles as sources of Fe,Zn, Pb, and Cd and partly of Cr, Ni, and Co. In winter when de-icing salt isused an increased concentration of heavy metals, especially of Fe and Zn, insoil was observed. Zinc can be used as an indicator element to demonstrate theeffect of traffic pollution in spring. In summer the mobility of Zn compoundsrises due to better aeration and the lowering of the pH of soil.
Key words: soil contamination, heavy metals, chlorides, traffic, studdedtires, road maintenance.
Determinationof lead in contaminated soils by graphite furnace atomic absorptionspectrometry for environmental risk assessment; 201–209
Lilli Paama, Hannu Rönkkömäki, Pekka Parvinen, and ToivoKuokkanen
Abstract. A simple and rapid graphite furnace atomicabsorption spectrometric (GF-AAS) technique was developed for the determinationof lead in soil samples taken from a skeet shooting area. The method wasevaluated by measuring some of the samples by inductively coupled plasma atomicemission spectrometry. Water and nitric acid extraction were used to determinethe easily soluble lead and the total lead in order to evaluate the mobility oflead in the ground. The precision (RSD) of the GF-AAS analysis ranged from 1.1%to 3.2%. The method was tested with determining the lead in the referencematerials CANMETC-Cu, PACS-2, and CRM
320. The results obtained were in goodagreement with the recommended values.
Key words: lead determination,contaminated soils, GF-AAS, ICP-AES, environmental risk assessment.
Instructions to authors; 210–212
Contents of volume 53; 213–214
