SASEV Journal Abstracts

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SASEV Journal Abstracts

The following research results, of which the abstracts are provided here, have been published in the South African Journal of Enology and Viticulture.

Development of an in vitro Dual Culture System for Grapevine and Xiphinema index as a Tool for Virus Transmission
P. Winterhagen¹, G. Brendel², G. Krczal¹ & G.M. Reustle¹
¹ RLP AgroScience GmbH, AlPlanta - Institute for Plant Research, Breitenweg 71, 67435 Neustadt / Weinstraße, Germany
² Rebschule Steinmann e. K., Sandtal 1, 97286 Sommerhausen, Germany
Grapevine fanleaf virus (GFLV) is a nepovirus that is transmitted to grapevines by the ectoparasitic nematode Xiphinema index. GFLV causes severe losses in yield and quality in viticulture worldwide. Presently, laborious and time-consuming field trials or greenhouse tests are necessary for screening putative GFLV resistance in new grape genotypes developed in breeding programmes. We developed an in vitro dual culture system for grapevines and nematode vectors that requires less time and space than inoculation experiments done in the greenhouse. Virus infection of in vitro grapevines was investigated using immunocapture-reverse transcriptase-polymerase chain reaction (IC-RT-PCR) analysis. The development of root galls induced by feeding nematodes on in vitro grapevines was also analysed. Virus infection in grapevines in the dual culture with viruliferous nematodes was detected six weeks post-inoculation. Root galls were always absent from parasitized in vitro grapevines with detectable virus infection, whereas they developed on some parasitized, but virus-negative tested grapevines. Therefore, root galls cannot be used as a reliable indicator for parasitism and virus transmission.
South African Journal Enology and Viticulture Volume 28 No. 1 2007 1 - 5

Characterisation of Colour Components and Polymeric Pigments of Commercial Red Wines by Using Selected UV-Vis Spectrophotometric Methods
A. Versari, G.P. Parpinello & A.U. Mattioli
Dipartimento di Scienze degli Alimenti, Università di Bologna, P.zza Goidanich 60, Cesena 47023, Italy
The composition of the colour components of commercial red wines from Italy was analysed in terms of total colour, co-pigmentation, SO2-resistant pigments, small and large polymeric pigments, and tannins. A total of 128 wines, including Sangiovese, Cabernet Sauvignon, Nero d’Avola, Merlot, Marzemino, Negroamaro, Aglianico, Cannonau and Rossese di dolceacqua from five vintages (1999 to 2003) were analysed. The composition of the wines showed significant differences in terms of total colour and co-pigmentation. Total colour at 520 nm was highest in Marzemino (7.50±1.5 AU, absorbance units), and then in Aglianico (7.10±2.8 AU) and Cabernet Sauvignon (5.01±2.50 AU). The level of large and small polymeric pigments in Sangiovese wines showed a range from 0.05 to 0.40 and 0.10 to 0.27 AU 520 nm respectively. The variation in the level of polymeric pigments is affected by a number of factors, including vintage, grape composition, fermentation and storage conditions.
South African Journal Enology and Viticulture Volume 28 No. 1 2007 6 - 10

Wine Dilates the Brachial Artery but does not Increase Flow-mediated Dilatation over Two Hours
D.M. Blackhurst, K.H. Wolmarans & A.D Marais
Lipidology Division of Internal Medicine, University of Cape Town Health Sciences Faculty, Anzio Road, Observatory 7925, South Africa
Epidemiological evidence suggests cardiovascular benefits from the consumption of alcoholic beverages, but corroboration by functional and outcome studies is still outstanding. Non-invasive functional tests on the brachial arteries of healthy volunteers were performed before and for two hours after consuming red wine. Brachial artery dimensions were determined by ultrasound at baseline, 30, 60 and 120 min. Flow-mediated dilatation (FMD) was similarly assessed. Putative minimum and maximum lumen diameters were determined after ice immersion and sublingual trinitroglycerine (TNG) at baseline and 60 min after wine consumption. Sixteen subjects had a mean resting brachial artery diameter of 3.84 mm, which significantly increased with wine to 4.44 mm at 30 min, 4.39 mm at 60 min and 4.49 mm at 120 min. The calculated blood flow rates during the study did not differ significantly over the measured intervals. The baseline mean diameter with TNG was not significantly different from the dilation with wine. The vasoconstrictor response varied, with a -2.6 ± 2.9% change with wine, compared with the baseline diameter. There was appreciable variation of the diameter relative to the range found with ice and TNG. The calculated FMDs (% changes) for the study were 10.8, 6.1, 5.6 and 7.5, indicating statistically significant effects of wine (p < 0.0001). The authors conclude that red wine consumption leads to beneficial arterial effects that may relate to different doses or other mechanisms than FMD. Further studies need to be done to discriminate between the effects of alcohol and phenolic compounds on vascular function.
South African Journal Enology and Viticulture Volume 28 No. 1 2007 11 - 16

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