Search

Les jaunisses de la vigne r?unissent un ensemble de maladies dont les sympt?mes sont identiques. La mise au point r?cente d'un test Elisa sp?cifique de la flavescence dor?e (FD) sur ?chantillon de vigne a permis de diff?rencier la FD des autres jaunisses. Ce test permet de d?tecter la FD sur diff?rents c?pages, au vignoble, et sur des porte-greffes, en serre, pr?sentant de l?gers sympt?mes. Il a ?t? appliqu? ? des ?chantillons de vigne provenant de r?gions diff?rentes du monde entier. La FD a ?t? localis?e ainsi dans le Sud de la France et le Nord de l'Italie (Friule). En France, ces r?sultats ont permis de clarifier la situation tr?s confuse concernant la pr?sence de la FD et du bois noir en Bourgogne, ainsi que dans les r?gions voisines. Les ?chantillons de Suisse, d'Italie (?milie romagne et Sicile), Australie, Isra?l, ?tats-Unis (?tat de New York), ainsi que ceux de l'Union Sud-Africaine infect?s par la maladie du Shiraz, ont r?agi n?gativement. Ces jaunisses n'ont donc pas de relation s?rologique avec la FD. Une telle enqu?te ne garantit pas l'absence de la FD dans les r?gions prospect?es, cependant, elle permet de mettre en ?vidence l'importance des autres jaunisses. Contribution to the study of grapevine yellows in the world: investigation by Elisa using flavescence dor?e-specific antibodies. Grapevine yellows (GY) are a group of diseases with similar symptoms. The recent publication on the use of Elisa to detect the flavescence dor?e (FD) mycoplasma-like organism (MLO) in the grapevine itself has allowed the differentiation of FD from the other GY. In order to investigate the epidemiology of FD, grapevine canes or leaves showing GY symptoms were harvested from several areas in the world (France, 138 samples; Northern Italy and Sicily, 13; Switzerland, 39; Israel, 9; North America, 31; South Africa, 24; and Australia, 26) and tested by Elisa using specific polyclonal and monoclonal antibodies raised against FD. FD-MLO were specifically detected in various cultivars from the field and in rootstock cuttings grown in the greenhouse and showing mild symptoms. In this work, FD was found to be confined to grapevine stocks in 2 regions of Europe: southern France and northern Italy (Friuli). In France, these results have allowed clarification of a very confusing situation concerning FD and Bois noir (BN). All the symptomatic vines of north-east France reacted negatively, and hence probably belong to BN. Some samples from the south of the Rh?ne valley (Ard?che) reacted similarly. No positive FD reaction was obtained with samples showing GY symptoms from Sicily, Emilia Romagna (Italy), Switzerland (western part and Tessin), Israel, USA (New York State), South Australia or with Shiraz decline desease from the Republic of South Africa. These results suggest that no serological relationship exists between FD-MLO and the other GY. However this study does not exclude that FD could be present in some parts of these areas. This work shows the economic importance of the GY other than FD, the risk of epidemics and the necessity to promote protecion, cure and eventual quarantine measures.

Two separate experiments were carried out to examine the effect of dietary protein intake on basal and GHstimulated plasma insulin-like growth factor-I (IGF-I) concentrations during either saline or glucose infusion into the jugular vein. In experiment 1, six castrated male lambs (27·1 ± 1·2 kg live weight (LW)) were fed a diet restricted in both metabolizable energy (ME; 0·18 MJ/kg LW per day) and nitrogen (2·0 g/kg LW per day) intakes, while in experiment 2 a further six lambs were fed a similar restricted ME intake but an increased nitrogen intake (3·0 g/kg LW per day). In both experiments glucose (experiment 1, 0·009 mmol/kg LW per min; experiment 2, 0·015 mmol/kg LW per min) or saline (0·25 ml/min) was infused for 6 days and plasma samples were obtained from the jugular vein at hourly intervals on day 4 (basal) or on days 5 and 6 after an i.v. GH challenge. In experiment 1 there was no increase in plasma IGF-I concentrations in response to the GH challenge during saline infusion, but during glucose infusion the plasma concentration of IGF-I increased to a peak after 24 h and declined over the next 20 h. Basal concentrations of IGF-I, insulin and glucose were significantly higher during glucose infusion. In experiment 2 the area under the IGF-I peak in response to the GH challenge was the same for the infusions of saline and glucose but the peak value for IGF-I was significantly higher during glucose infusion due to higher concentrations in the basal period. It is concluded that feeding a dietary intake of metabolisable energy and nitrogen which is only just sufficient to meet the requirements for maintenance of body tissues completely abolishes the increase in plasma IGF-I in response to GH challenge. Increasing the nitrogen supply in the diet or i.v. infusion of glucose re-establishes the IGF-I response to GH challenge as well as increasing basal IGF-I concentrations. The potential involvement of circulating concentrations of insulin, glucose and amino acids in the control of plasma IGF-I levels are discussed.Journal of Endocrinology(1992) 132,195–199