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Z Vucinić

Publications and source records attributed to Z Vucinić.

13 recordsLinked to original sources
PubMed2005

Superoxide dismutase, peroxidase, and germin-like protein activity in plasma membranes and apoplast of maize roots.

The analysis of plasma membranes from maize roots by native gel electrophoresis revealed the existence of Mn-containing 120 kDa and CuZn-containing 70, 40, and 15 kDa superoxide dismutase (SOD) isoform activities. Isoelectric focusing of the plasma membranes differentiated anionic SOD isoforms with a pI of about 5 and cationic SOD isoforms at pI 8.6. Solubilization of the plasma membrane proteins further separated the cationic SOD into pI 8.6, 8.2, 8.4, and 7.2 isoforms. Double staining for both SOD and peroxidase activities showed an overlap of these activities only in the case of the high-molecular-mass (ca. 120 kDa) isoforms. High-temperature treatments demonstrated that the 120 kDa isoform was active even at 100 degrees C, indicating that it was a germin-like protein with superoxide-dismutating activity, different from the peroxidase with a similar molecular mass and the lower-molecular-mass CuZn-containing superoxide dismutases. These results are compared to those obtained from whole-tissue extract and apoplastic fluid.

Cell Membrane↗
PubMed2003

Superoxide synthase and dismutase activity of plasma membranes from maize roots.

Superoxide synthase and superoxide dismutase activity have been monitored in isolated maize ( Zea mays) root plasma membranes spectrophotometrically by determination of nitro-blue tetrazolium and cytochrome c reduction, respectively. Superoxide production was induced by NADH and NADPH, with similar kinetics and approaching saturation at 0.06 mM in the case of NADPH and 0.1 mM in the case of NADH, with rates of 18.6 +/- 5.0 and 21.8 +/- 7.2 nmol/min. mg of protein, respectively. These activities exhibited a broad pH optimum between pH 6.5 and 7.5. Diphenylene iodonium inhibited about 25% (10 microM DPI) and 40% (100 microM DPI) of this activity, imidazole inhibited about 20%, while KCN, a peroxidase inhibitor, did not show any significant inhibition. Superoxide-dismutating activity was shown to occur in the same isolates and depended on the quantity of plasma membrane protein present. Growth of plants on salicylic acid prior to membrane isolation induced a rise in the activity of both of the enzymes by 20-35%, suggesting their coordinated action.

Cell Membrane↗
PubMed1996

Involvement of plasma membrane redox system in the generation of trans-root electrical potential difference in excised maize root.

Possible involvement of the plasma membrane bound redox system in the generation of the trans-root electrical potential difference (TRP) arising across 8 day old maize (Zea mays L. hybrid ZPSC704) roots was studied. Excised roots were exposed to artificial impermeable electron acceptors (potassium hexacyanoferrate III and potassium hexachloroiridate IV) in external solution, and TRP response, oxygen consumption rate, proton efflux and reduction of the electron acceptors were analyzed. The effect of hexacyanoferrate III (HCF III) was tested at three concentrations (0.1; 0.5 and 1.0 mmol/l), and hexachloroiridate IV (HCI IV) in the concentration range 10(-7)-5.10(-4) mol/l. Both electron acceptors depolarized the trans-root potential, an order of magnitude lower concentrations of hexachloroiridate producing a much more rapid depolarization of greater magnitude. The roots had a higher capacity to reduce 0.1 mmol/l hexachloroiridate than 1 mmol/l hexacyanoferrate. Also, an increased level of acidification induced by HCI IV than HCF III could be observed. The rate of oxygen consumption showed an increase of about 20% in both cases. These results prove that electron transplasma membrane transport process(es) contribute to the total trans-root electrical potential difference across an excised maize root.

Cell Membrane↗
PubMed1985

Electrogenic proton pump in Nitella and the effect of calcium.

The hyperpolarisation of the membrane potential in Characeae above that of the diffusion potential is explained by the operation of the electrogenic proton pump. We studied the interaction of calcium with the functioning of the pump. The membrane potential was measured using the standard microelectrode technique. An increase in the calcium concentration resulted in depolarisation, its magnitude increasing with lower proton concentrations. Calcium-induced membrane potential changes, tested in the concentration range of 0.25 mmol/l to 25 mmol/l, were greatest at 0.25 mmol/l CaCl2 and decreased with the increasing calcium concentration. Light-induced initial changes in the membrane potential also showed a dependence on the presence of calcium in the external medium. We conclude that calcium has a role in the regulation of the proton pump in Nitella.

Calcium↗
PubMedDate not supplied

Effect of propagators and inhibitors on the ultraweak luminescence from maize roots.

This study has investigated the kinetics and mechanism of ultraweak luminescence in maize roots. Mannitol induced the second maximum and enhanced the main maximum of the relative intensity of luminescence from the roots. Hydroquinone and quinone enhanced the relative intensity of the luminescence. Catalase enhanced the maximum of the luminescence and changed the kinetics of the light emission. The effect of catalase on the kinetics was abolished by superoxide dismutase. Ascorbate in the presence of catalase on the kinetics was abolished by superoxide dismutase. Ascorbate in the presence of catalase reduced the luminescence maximum, but did not alter the kinetics. In the presence of catalase only, or in the combination with superoxide dismutase, or ascorbate, the luminescence intensity in the stationary phase was significantly lower compared to the control. The results support the participation of superoxide-radical, singlet oxygen, electron transfer and the role of peroxidase in the reactions generating ultraweak luminescence in the roots. Ascorbate, catalase and superoxide dismutase have a protective role in the luminescent reactions.

Ascorbic Acid↗
PubMedDate not supplied

[The effect of cell phones on pacemaker function].

UNLABELLED: The aim of the study was to examine if there existed a risk from interference of cellular phones on patients with implanted permanent pacemakers. The study comprised 144 patients (134 VVI/VVIR and 10 DDD/DDDR) with permanent pacemakers of different manufactures. METHODS: During the routine pacemaker check, cellular phone aerial (Nokia 1610; GSM Standard) was placed against the skin of patients above the spot of pacemaker implantation, while the phone calls were repeated and ECG was continuously monitored. The effect of cellular phone on pacemaker was established upon: a) preexisting parameters of electric pacemaker stimulation; b) minimal ventricular rate of 90 beats/min, while electric stimulation parameters were set to their most sensitive values (MSV). RESULTS: Only in 9 (6.25%) patients was observed intermittent pacemaker inhibition, when pacemaker settings were on preexisting values of electric stimulation, while in 17 patients (11.8%) inhibition was noticed, when pacemaker settings were changed to their MSV. Besides, programmed values of electric stimulation in our patients remained unchanged. CONCLUSION: Although the electromagnetic interference interactions of cellular phones on pacemaker function were observed in relatively small number of our patients, we were of the opinion that pacemaker-dependent patients should avoid the use of cellular phones.

Adult↗
PubMedDate not supplied

Factors influencing the degree and outcome of acute beta-blockers poisoning.

Since severe and fatal poisoning with beta-blockers due only to beta-receptor blockade is unlikely, a prospective and partly retrospective analysis of 67 patients with beta-blockers poisoning was done in five-year period in order to determine the factors influencing the degree and outcome of acute poisoning. According to pharmacological properties of drugs, the patients were divided in groups: group I--50 patients with propranolol, group II-A--10 patients with atenolol and group II-B--7 patients with metoprolol poisoning. Electrocardiogram (ECG), 24-h ECG monitoring, toxicological screening (determination of beta-blockers in blood, urine and lavage by high performance liquid chromatography) and biochemical analysis were performed in all patients. Significantly smaller number of patients with serious poisoning was observed in group II-B. Patient's age did not correlate with the degree of poisoning, but significant correlation was found between preexisting disease, ingested dose and the time elapsed before the treatment started. Analysis of pharmacological properties showed that membrane stabilizing activity and lipophilicity of the drug might be the important determinants of the toxicity, while the role of cardioselectivity was lost in an overdose.

Acute Disease↗
PubMedDate not supplied

[Successful surgical removal of a cardiac myxoma from the left ventricular outflow tract].

The precondition for successful, exclusively surgical treatment in the extracorporeal circulation, is the precise diagnosis of heart myxoma, particularly in rare locations such as the left ventricle. We present a case of myxoma in the outflow tract of the left ventricle as the exceptionally rare location, successfully diagnosed and surgically treated at the Clinic for Cardiac and Thoracic Surgery of the Military Medical Academy. A female patient, aged 46 years, was sent from another hospital with misdiagnosis of idiopathic hypertrophic subaortic stenosis. The patient was successfully operated after transthoracic and transesophageal echocardiography as the main diagnostic procedures. Myxoma that completely obstructed the aortic opening if pulled, was completely removed through aortic valve in the extracorporeal circulation. Its pedicle was arising from the ventricular side of the great mitral cusp. Postoperative course was uneventful and the patient was released from the hospital on the tenth postoperative day.

Echocardiography↗