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At least 253 records · Page 14Linked to original sources
PubMed1987

Dynamic Relation between Expansion and Cellular Turgor in Growing Grape (Vitis vinifera L.) Leaves.

Measurements of the growth and water relations of expanding grape (Vitis vinifera L.) leaves have been used to determine the relationship between leaf expansion rate and leaf cell turgor. Direct measurement of turgor on the small (approximately 15 micrometer diameter) epidermal cells over the midvein of expanding grape leaves was made possible by improvements in the pressure probe technique. Leaf expansion rate and leaf water status were perturbed by environmentally induced changes in plant transpiration. After establishing a steady state growth rate, a step decrease in plant transpiration resulted in a rapid and large increase in leaf cell turgor (0.25 megapascal in 5 minutes), and leaf expansion rate. Subsequently, leaf expansion rate returned to the original steady state rate with no change in cell turgor. These results indicate that the expansion rate of leaves may not be strongly related to the turgor of the leaf cells, and that substantial control of leaf expansion rate, despite changes in turgor, may be part of normal plant function. It is suggested that a strictly physical interpretation of the parameters most commonly used to describe the relationship between turgor and growth in plant cells (cell wall extensibility and yield threshold) may be inappropriate when considering the process of plant cell expansion.

Journal Article↗
PubMed1988

Resistance to Water Transport in Shoots of Vitis vinifera L. : Relation to Growth at Low Water Potential.

Apparent resistances to water transport in the liquid phase were determined from measurements of soil, root, basal shoot internode, shoot apex, and leaf water potentials and water flux in Vitis vinifera (cv White Riesling) during soil drying. Predawn water potential differences (DeltaPsi) in the shoots accounted for 20% of the total DeltaPsi between the soil and the shoot apex when plants were well-watered but increased to about 90% when shoot growth ceased. The DeltaPsi from soil to root was essentially constant during this period. At low water potential, the DeltaPsi in the shoot was persistent when transpiration was low (predawn) or completely prevented (plant bagging). The apparent hydraulic resistance between the basal shoot internode and most rapidly expanding leaf (or shoot apex) increased several-fold when water was withheld. Leaf and internode expansion both exhibited high sensitivity to increasing hydraulic resistance. Measurements of pneumatic resistance to air flow through frozen internode segments indicated progressive vapor-filling of vessels as soil drying progressed. From these observations and others in the literature, it was suggested that embolization may be a common occurrence and play an important role in the inhibition of shoot growth at moderate water deficits.

Journal Article↗
PubMed1989

Effects of Ambient and Acute Partial Pressures of Ozone on Leaf Net CO(2) Assimilation of Field-Grown Vitis vinifera L.

Mature, field-grown Vitis vinifera L. grapevines grown in open-top chambers were exposed to either charcoal-filtered air or ambient ozone partial pressures throughout the growing season. Individual leaves also were exposed to ozone partial pressures of 0.2, 0.4, or 0.6 micropascals per pascal for 5 hours. No visual ozone damage was found on leaves exposed to any of the treatments. Chronic exposure to ambient O(3) partial pressures reduced net CO(2) assimilation rate (A) between 5 and 13% at various times throughout the season when compared to the filtered treatment. Exposure of leaves to 0.2 micropascals per pascal O(3) for 5 hours had no significant effect on A; however, A was reduced 84% for leaves exposed to 0.6 micropascals per pascal O(3) when compared to the controls after 5 hours. Intercellular CO(2) partial pressure (c(i)) was lower for leaves exposed to 0.2 micropascals per pascal O(3) when compared to the controls, while c(i) of the leaves treated with 0.6 micropascals per pascal of 0(3) increased during the fumigation. The long-term effects of ambient O(3) and short-term exposure to acute levels of O(3) reduced grape leaf photosynthesis due to a reduction in both stomatal and mesophyll conductances.

Journal Article↗
PubMed1990

Photoinhibition in Vitis californica: The Role of Temperature during High-Light Treatment.

Leaves of Vitis californica Benth. (California wild grape) exposed to a photon flux density (PFD) equivalent to full sun exhibited temperature-dependent reductions in the rates or efficiencies of component photosynthetic processes. During high-PFD exposure, net CO(2) uptake, photon yield of oxygen evolution, and photosystem II chlorophyll fluorescence at 77 Kelvin (F(m), F(v), and F(v)/F(m)) were more severely inhibited at high and low temperatures than at intermediate temperatures. Sun leaves tolerated high PFD more than growth chamber-grown leaves but exhibited qualitatively similar temperature-dependent responses to high-PFD exposures. Photosystem II fluorescence and net CO(2) uptake exhibited different sensitivities to PFD and temperature. Fluorescence and gas exchange kinetics during exposure to high PFD suggested an interaction of multiple, temperature-dependent processes, involving both regulation of energy distribution and damage to photosynthetic components. Comparison of F(v)/F(m) to photon yield of oxygen evolution yielded a single, curvilinear relationship, regardless of growth condition or treatment temperature, whereas the relationship between F(m) (or F(v)) and photon yield varied with growth conditions. This indicated that F(v)/F(m) was the most reliable fluorescence indicator of PSII photochemical efficiency for leaves of different growth conditions and treatments.

Journal Article↗
PubMed1990

Immunocharacterization of NADH-Glutamate Dehydrogenase from Vitis vinifera L.

Rabbit antiserum was raised against NADH-glutamate dehydrogenase (GDH) isoenzyme 1, purified from leaves of Vitis vinifera L. cv Soultanina and its specificity was tested. This antiserum was used for immunocharacterization of the GDH from leaf, shoot, and root tissues. The antiserum recognized the seven isoenzymes of NADH-GDH and precipitated all the enzyme activity from the three tissues tested. Western blot following SDS-PAGE revealed the same protein band for the three tissues, with a molecular mass of 42.5 kilodaltons corresponding to NADH-GDH subunit. Results, based on the immunological studies, revealed that NADH-GDH from leaf, shoot, and root tissues are closely related proteins. Furthermore, addition of ammonium ions to the culture medium of in vitro grown explants resulted in a significant increase in NADH-GDH activity in root, shoot, and leaf tissues.

Journal Article↗
PubMed2004

Polyamines and somatic embryogenesis in two Vitis vinifera cultivars.

Polyamine content and activities of enzymes of polyamine biosynthesis were assayed during somatic embryogenesis in Vitis vinifera callus cultures of Chardonnay and Brachetto 'a grappolo lungo' (Brachetto g.l.) cultivars. The analyses were carried out on embryogenic callus samples, embryos at different stages and developing plants. Polyamine content, both in the free and PCA-soluble conjugated form, was higher in Brachetto g.l. than in Chardonnay, and putrescine was present at higher concentrations than the other polyamines. In all samples of both cultivars, ornithine decarboxylase activity (ODC, EC 4.1.1.17) was higher than arginine decarboxylase (ADC, EC 4.1.1.19), with a maximum in developing plant roots. S-Adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.50) activity displayed a similar trend. The activities of all three enzymes were detected both in the supernatant and pellet fractions, indicating for the first time the presence of SAMDC activity in the particulate fraction. Particularly in the Chardonnay cultivar, an increase in the mRNAs expression patterns of ODC and SAMDC during morphogenesis from small embryos to plantlets was detected by northern blot, suggesting a direct correlation with enzymatic activities.

Journal Article↗
PubMed1999

Structure and function of a conserved DNA region coding for tartrate utilization in Agrobacterium vitis.

Three tartrate utilization regions from Agrobacterium vitis strains involved in host specificity have been compared, to clearly define the borders of these regions and eventually identify specific sequences that could provide a mechanism of duplication of this region. A 10.8-kb conserved DNA fragment called the TAR element, found in different genetic contexts, was defined. A comparison of the two tartrate dehydrogenase genes (ttuC and ttuC') in each of the three TAR elements suggests that these genes co-evolve.

Alcohol Oxidoreductases↗
PubMed2000

Enhancement of in vitro growth and resistance to gray mould of Vitis vinifera co-cultured with plant growth-promoting rhizobacteria.

The potential of a plant growth-promoting rhizobacterium, Pseudomonas sp. (strain PsJN), to stimulate the growth and enhancement of the resistance of grapevine (Vitis vinifera L.) transplants to gray mould caused by Botrytis cinerea has been investigated. In vitro inoculation of grapevine plantlets induced a significant plant growth promotion which made them more hardy and vigorous when compared to non-inoculated plantlets. This ability increased upon transplanting. When grown together with B. cinerea, the causal agent of gray mould, significant differences of aggressiveness were observed between the inoculated and non-inoculated plants. The presence of bacteria was accompanied by an induction of plant resistance to the pathogen. The beneficial effect from this plant-microbe association is being postulated.

Botrytis↗
PubMed2001

Elevated temperature differentially affects virulence, VirB protein accumulation, and T-pilus formation in different Agrobacterium tumefaciens and Agrobacterium vitis strains.

That gene transfer to plant cells is a temperature-sensitive process has been known for more than 50 years. Previous work indicated that this sensitivity results from the inability to assemble a functional T pilus required for T-DNA and protein transfer to recipient cells. The studies reported here extend these observations and more clearly define the molecular basis of this assembly and transfer defect. T-pilus assembly and virulence protein accumulation were monitored in Agrobacterium tumefaciens strain C58 at different temperatures ranging from 20 degrees C to growth-inhibitory 37 degrees C. Incubation at 28 degrees C but not at 26 degrees C strongly inhibited extracellular assembly of the major T-pilus component VirB2 as well as of pilus-associated protein VirB5, and the highest amounts of T pili were detected at 20 degrees C. Analysis of temperature effects on the cell-bound virulence machinery revealed three classes of virulence proteins. Whereas class I proteins (VirB2, VirB7, VirB9, and VirB10) were readily detected at 28 degrees C, class II proteins (VirB1, VirB4, VirB5, VirB6, VirB8, VirB11, VirD2, and VirE2) were only detected after cell growth below 26 degrees C. Significant levels of class III proteins (VirB3 and VirD4) were only detected at 20 degrees C and not at higher temperatures. Shift of virulence-induced agrobacteria from 20 to 28 or 37 degrees C had no immediate effect on cell-bound T pili or on stability of most virulence proteins. However, the temperature shift caused a rapid decrease in the amount of cell-bound VirB3 and VirD4, and VirB4 and VirB11 levels decreased next. To assess whether destabilization of virulence proteins constitutes a general phenomenon, levels of virulence proteins and of extracellular T pili were monitored in different A. tumefaciens and Agrobacterium vitis strains grown at 20 and 28 degrees C. Levels of many virulence proteins were strongly reduced at 28 degrees C compared to 20 degrees C, and T-pilus assembly did not occur in all strains except "temperature-resistant" Ach5 and Chry5. Virulence protein levels correlated well with bacterial virulence at elevated temperature, suggesting that degradation of a limited set of virulence proteins accounts for the temperature sensitivity of gene transfer to plants.

Agrobacterium tumefaciens↗
PubMed1995

A molecular marker based linkage map of Vitis.

Genetic linkage maps of Vitis (2n = 38) have been constructed from a single interspecific hybrid grape population (60 seedlings) of 'Cayuga White' X 'Aurore'. The maps were primarily based on 422 RAPD markers but also included 16 RFLP and isozyme markers. These maps had an average distance of 6.1 cM between markers and were developed using a double-pseudotestcross strategy. The 'Cayuga White' map had 214 markers covering 1196 cM and that of 'Aurore' spanned over 1477 cM with 225 markers. The 'Cayuga White' map consisted of 20 linkage groups, whereas 22 linkage groups comprised the 'Aurore' map. The number of groups reduced to 19, as in some instances two or more groups from one parent showed homology with a single group from the other parent on the basis of markers heterozygous in both parents. Each linkage group ranged in size from 14 to 135 cM in 'Aurore' and from 14 to 124 cM in 'Cayuga White'. These maps provide enough coverage of the genome to allow quantitative trait locus analysis and map-based gene cloning.

Base Sequence↗
PubMed1996

Targetting and optomotor space in the leaf-hopper Empoasca vitis (Gothe) (Hemiptera: Cicadellidae)

The accuracy with which the visuomotor system of Empoasca vitis can prescribe a jump trajectory towards a bright, uniformly illuminated target shape was investigated. The targets consisted of discs, rings or bars cut out of black card and mounted in front of a source of stroboscopic light diffused through translucent paper. The targets varied in size, subtending angles of 7-110 ° to the insect's eye. Target resolution was measured independently along the horizontal and vertical axes and was defined in terms of the standard deviation of the horizontal (s.d.x) or vertical (s.d.y) angular coordinates of the take-off paths measured with respect to the geometric centre of the target. In all cases involving single connected images, the point towards which jumping was directed coincided with the geometric centre of the image area (the light centroid). This meant, for example, that the insects specifically targetted the dark core of a ring of light. No formal features of the target shapes, such as light-dark boundaries, were targetted. Vertical axial resolution was independent of image size (mean s.d.y for all image sizes 6.9 °), but horizontal axial resolution only achieved this minimal value at intermediate image sizes (approximately 30-60 °). When two separate but identical target shapes (vertical bars) were presented at different horizontal separations, the dark area between them was accurately targetted up to target separations of approximately 30-50 °. At greater separations, there was an increasing tendency to target one or other of the two shapes. From these experiments it is concluded that, in the frontal visual field, spatial integration can be performed to an accuracy (as defined in these experiments) of 7 °x7 °. Performance deteriorates outside an optimal range of image sizes, and this is faithfully reflected in the decline in horizontal axial resolution when jumping. However, this decline in visual performance is not reflected in target resolution along the vertical axis because it is masked by a biomechanical constraint, i.e. the inability of the legs to set take-off angles outside a narrow range of 30-60 ° to the horizontal.

Journal Article↗
PubMed2000

An immunohistochemical study of the compartmentation of metabolism during the development of grape (Vitis vinifera L.) berries.

The compartmentation of key processes in sugar, organic acid and amino acid metabolism was studied during the development of the flesh and seeds of grape (Vitis vinifera L.) berries. Antibodies specific for enzymes involved in sugar (cell wall and vacuolar invertases, pyrophosphate: fructose 6-phosphate phosphotransferase, aldolase, NADP-glyceraldehyde-P dehydrogenase, cytosolic fructose 1,6-bisphosphatase), photosynthesis (Rubisco, fructose 1,6-bisphosphatase, sedoheptulose 1,7-bisphosphatase), amino acid metabolism (cytosolic and mitochondrial aspartate aminotransferases, alanine aminotransferase, glutamate dehydrogenase, glutamine synthetase), organic acid metabolism (phosphoenolpyruvate carboxylase, NAD- and NADP-dependent malic enzyme, ascorbate peroxidase), and lipid metabolism (acetyl CoA carboxylase, isocitrate lyase) were used to determine how their abundance changed during development. There were marked changes in the abundance of many of these enzymes in both the flesh and seeds. The intercellular location of some enzymes was investigated using immunohistochemistry. Several enzymes (e.g. phosphoenolpyruvate carboxylase and those involved in amino acid metabolism) were associated with tissues likely to function in the transport of imported assimilates, such as the vasculature. Although other enzymes (e.g. NADP-malic enzyme and soluble acid invertase, involved in the metabolism of sugars and organic acids) were largely present in the parenchyma cells of the flesh, their distribution was extremely heterogeneous. This study shows that when considering the metabolism of complex structures such as fruit, it is essential to consider how metabolism is compartmentalized between and within different tissues, even when they are apparently structurally homogeneous.

Amino Acids↗
PubMed1997

[Determination of arbutin in the herbs of Vaccinium vitis-idaea L. by RP-HPLC].

Determination of arbutin in the herbs of Vaccinium vitis-idaea has been carried out by RP-HPLC, using Inertsil-ODS column (4.6 mm x 250 mm) and mobile phase of methanol and water (15:85), and detecting at 280 nm wavelength. The average content of arbutin is 4.44%, RSD = 2.93%; the recovery rate is 100.7%, RSD = 2.85%.

Arbutin↗
PubMed2000

Antioxidant activity of polyphenols from seeds of Vitis amurensis in vitro.

AIM: To study the antioxidant action of five polyphenols (+) catechin, procyanidin B2, procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin isolated from the seeds of Vitis amurensis. METHODS: The mouse liver homogenate lipid peroxidation assay was applied for the evaluation of the antioxidant activity in vitro. RESULTS: (+) Catechin, procyanidin B2, procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin showed antioxidant activity with the IC50 values of 0.47, 0.25, 0.10, 0.02, and 0.03 mmol/L, respectively. The IC50 value of vitamin E used as a positive control was 0.13 mmol/L. The structural activity relationship was also analyzed. Procyanidins carrying a galloyl group possessed higher anti-lipid peroxidation activities. All dimers were found to be more potent than the non-galloylated momomer such as (+) catechin. However, the activity of the 4-->6 linked dimer seemed more preferable than 4-->8 linked dimer. CONCLUSION: Procyanidin B5, procyanidin B5 3'-O-gallate, and amurensisin showed a more antioxidant activity than vitamin E did, and their activity is dependent on their substitution and polymerization patterns.

Animals↗
PubMed1992

Identification of closely related Agrobacterium vitis isolates by chromosomal DNA probes.

Crown gall formation on grapevine by Agrobacterium vitis is an important plant disease in many regions of the world. On grapevine, octopine/cucumopine (o/c) strains are widely distributed. Here we describe two chromosomal sequences of o/c strains of 15 and 20 kb, which reveal a high degree of polymorphism in different o/c isolates. Part of the polymorphism is due to the presence or absence of a 2.2-kb-long repeated sequence, a homolog of which is also found on the octopine Ti plasmid of Ach5, immediately to the left of the left TL-region border. The occurrence and distribution of this repeat in different o/c isolates make it possible to reconstruct the evolution of these strains. The chromosomal DNA sequences outside the repeats also differ in various isolates. The two probes described here can be used to identify strains from a collection, classify new isolates, or trace a given isolate under experimental release conditions.

Base Sequence↗
PubMed2003

Characterization of a class III chitinase from Vitis vinifera cv. Koshu.

A chitinase gene (Chi3K) was cloned from the genomic DNA of Vitis vinifera cv. Koshu. The structural gene comprised 891 by without introns and encoded 297 amino acids. The Chi3K product showed high similarity to the class III chitinase of V. vinifera cv. Pinot noir. Chi3K was expressed using a bacterial expression vector for purification and enzymatic characterization of its gene product. The recombinant chitinase exhibited hydrolytic activity toward glycol chitin and its optimum pH was 4.0. It also inhibited the growth of Botrytis cinerea, which causes grey mold disease in grapes.

Journal Article↗
PubMed1994

Free radicals scavenging action and anti-enzyme activities of procyanidines from Vitis vinifera. A mechanism for their capillary protective action.

The scavenging by procyanidines (polyphenol oligomers from Vitis vinifera seeds, CAS 85594-37-2) of reactive oxygen species (ROS) involved in the onset (HO degrees) and the maintenance of microvascular injury (lipid radicals R degrees, RO degrees, ROO degrees) has been studied in phosphatidylcholine liposomes (PCL), using two different models of free radical generation: a) iron-promoted and b) ultrasound-induced lipid peroxidation. In a) lipid peroxidation was assessed by determination of thiobarbituric acid-reactive substances (TBARS); in b) by determination of conjugated dienes, formation of breakdown carbonyl products (as 2,4-dinitrophenylhydrazones) and loss of native phosphatidylcholine. In the iron-promoted (Fenton-driven) model, procyanidines had a remarkable, dose-dependent antilipoperoxidant activity (IC50 = 2.5 mumol/l), more than one order of magnitude greater than that of the monomeric unit catechin (IC50 = 50 mumol/l), activity which is due, at least in part, to their metal-chelating properties. In the more specific model b), which discriminates between the initiator (hydroxyl radical from water sonolysis) and the propagator species of lipid peroxidation (the peroxyl radical, from autooxidation of C-centered radicals), procyanidines are highly effective in preventing conjugated diene formation in both the induction (IC50 = 0.1 mumol/l) and propagation (IC50 = 0.05 mumol/l) phases (the scavenging effect of alpha-tocopherol was weaker, with IC50 of 1.5 and 1.25 mumol/l). In addition, procyanidines at 0.5 mumol/l markedly delayed the onset of the breakdown phase (48 h), totally inhibiting during this time the formation of degradation products (the lag-time induced by alpha-tocopherol was only of 24 h at 10 mumol/l concentration). The HO degrees entrapping capacity of these compounds was further confirmed by UV studies and by electron spin resonance (ESR) spectroscopy, using DMPO as spin trapper: procyanidines markedly reduced, in a dose-dependent fashion, the signal intensity of the DMPO-OH radical spin adduct (100% inhibition at 40 mumol/l). The results of the second part of this study show that procyanidines, in addition to free radical scavenging action, strongly and non-competitively, inhibit xanthine oxidase activity, the enzyme which triggers the oxy radical cascade (IC50 = 2.4 mumol/l). In addition procyanidines non-competitively inhibit the activities of the proteolytic enzymes collagenase (IC50 = 38 mumol/l) and elastase (IC50 = 4.24 mumol/l) and of the glycosidases hyaluronidase and beta-glucuronidase (IC50 = 80 mumol/l and 1.1 mumol/l), involved in the turnover of the main structural components of the extravascular matrix collagen, elastin and hyaluronic acid.(ABSTRACT TRUNCATED AT 400 WORDS)

Biflavonoids↗