1,721,001 research outputs found
Modulation of viral infection in plants by exogenous guanosine
Full text linkTo evaluate the role of purines in antiviral treatments in plants, ribavirin (RB) and tiazofurin (TZ) were applied in combination with guanosine (GS) or adenosine (AS) in in vitro grapevine or tobacco explants infected by Grapevine leafroll associated virus 3 (GLRaV-3) and Cucumber mosaic virus (CMV), respectively. Using a microelectrochemical (trans-plasma membrane electron transport, t-PMET) technique, in vivo assay of free reduced nicotinamide adenine dinucleotide (NADH) was also carried out to estimate the inosine monophosphate dehydrogenase inhibition caused by drugs. Antiviral effectiveness of TZ, evaluated as virus-free explants or virus copies, was significantly hindered by GS in both species, while AS did not interfere with the drugs. GS, but not AS, slightly hindered the antiviral effectiveness of RB. With regard to NADH tests, t-PMET inhibition caused by RB and TZ was dose dependent and the interference of drugs with the NAD+/NADH conversion was confirmed by NADH content. Findings indicate that exogenous GS up to 0.50 mM replenished the GS pool depleted by drugs, contrasting antiviral action. At higher doses of GS, the TZ antiviral action was completely inhibited and exogenous GS caused a feedback that reduced t-PMET activity. The reversal was partially against RB, suggesting that the reduction of the GS pool contributed to the antiviral activity of RB, but it was not the only cause of antiviral effectiveness
Effect of mycophenolic acid on trans-plasma membrane electron transport and electric potential in virus-infected plant tissue
No full textMycophenolic acid (MPA) is an inosine monophosphate dehydrogenase inhibitor whose antiviral mechanism of action is supposed to interfere with NAD(+)/NADH conversion. Its effects on trans-plasma membrane electron transport (t-PMET) and on trans-plasma membrane electric potential (t-PMEP), which are involved in the NAD(+)/NADH conversion, were investigated using microelectrochemical techniques in tobacco plants infected by Cucumber mosaic virus. In these tests, ferricyanide (Fe(3+)) was used as electron acceptor in assays performed with intact cells; ferricyanide is converted to ferrocyanide (Fe(2+)) by one-electron reduction, and the rate of this reduction can be monitored in order to investigate the effects on t-PMET or t-PMEP. Considering tests on t-PMEP, MPA treatment of samples induced membrane depolarization and this effect was greater in healthy samples compared to infected ones. In any case, complete repolarization was achieved, indicating no irreversible damage to the membrane due to MPA administration. Moreover, in samples pre-treated with MPA, the extent of depolarization caused by Fe(3+) administration was lower than in samples without pre-treatment but the MPA effect was not related to virus infection. With regard to tests on t-PMET, MPA caused a reduction in Fe(3+)/Fe(2+) conversion compared to untreated plants. However, infected samples were less sensitive to MPA treatment, which may be due to the concurrent entry of MPA within the symplast that, as indicated by t-PMEP tests, was lower in infected samples. In conclusion, MPA interferes with membrane activity linked to NAD(+)/NADH conversion, acting differently in infected or healthy samples during drug uptake by cells
Application of tracking implants in grape hybrids: Adjustments to production practices and new health-compliant methodologies
No full textMembrane transport of antiviral drugs in plants: an electrophysiological study in grapevine explants infected by Grapevine leafroll associated virus 1
No full textUltra-High Frequency transponders in grapevine: A tool for traceability of plants and treatments in viticulture
No full textImplanting RFIDs into Prunus to facilitate electronic identification in support of sanitary certification
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Ultra-High Frequency transponders in grapevine: A toolfor traceability of plants and treatments in viticulture
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