Chicks and chickens maintained under commercial conditions were vaccinated against Newcastle Disease via drinking water. Prior and after different times of vaccination blood samples were drawn from different numbers of birds and checked for HI antibodies. The modes of distribution of the antibody titers within the random sample were assayed. The following results were obtained:
1. 1. On the basis of the distribution of the serum titers can be concluded whether the antibody level within a flock is increasing or decreasing.
◦ —A right steep asymmetry can be observed up to 20 days post vaccination.
◦ —In the phase of maximal antibody levels an almost symmetric distribution of the titers is present.
◦ —In later times (more than three weeks p. vacc.) the distribution shows a left steep asymmetry (Poisson distribution).
2. 2. A poisson distribution is also observable during the elimination of maternal antibodies of chicks until complete elimination.
3. 3. The mode of distribution of the HI titers in sera of day-old chicks correlates with the mode of distribution of the dams. Therefore, conclusions are possible from the status of the chicks to the dams and reverse.
4. 4. Factors which interfere with the mode of distribution are:
◦ —Two or more peaks after vaccination of chickens. This indicates an uneven immune response within the flock.
◦ —Distributions with several peaks may also occur if flocks are composed of day-old chicks from parent flocks with different levels of antibody titers.
Résumé
Des poulets et des poussins maintenus dans un élevage conventionnel furent vaccinés contre la maladie de Newcastle par un vaccin administré dans l'eau de boisson. Avant et à différents temps après vaccination, des échantillons de sang furent prélevés sur un certain nombre de poussins et les anticorps inhibants de l'hémagglutination furent recherchés. Les modes de la distribution des titres en anticorps pour les échantillons pris au hasard furent recherchés. Les résultats suivants furent obtenus:
1. 1. Sur la base de la distribution des titres sériques, on peut conclure si le taux en anticorps à l'intérieur d'une population a augmenté ou diminué.
◦ —Une courbe asymétrique avec un pic déplacé vers la droite peut être observée 20 jours après la vaccination.
◦ —La phase correspondant au taux maximal en anticorps présente une distribution presque normale.
◦ —Plus tard, (au-delà de 3 semaines après la vaccination), la distribution apparaît asymétrique avec un déplacement vers la gauche (distribution de Poisson).
2. 2. Une distribution de Poisson peut aussi être observée au moment de l'élimination des anticorps d'origine maternelle chez des poussins jusqu'à complète élimination.
3. 3. Le mode de distribution des titres en anticorps inhibant l'hémagglutination dans des sérums de poussins d'un jour correspond au mode de distribution observé chez les mères. Des conclusions peuvent donc être faites à partir de l'état immunologique des poussins vis-à-vis des mères et viceversa.
4. 4. Les facteurs qui peuvent intervenir dans le mode de distribution sont:
◦ —Deux pics ou plus après la vaccination des poussins. Ceci indique qu'il existe une réponse immunitaire inégale dans la population.
◦ —Des distributions avec plusieurs pics peuvent être également observées si les populations sont composées de poussins de un jour provenant de populations parentales ayant des taux différents de titres en anticorps.
L11A-Fukushima (L11A-F) derived from attenuated isolate LuA of Tomato mosaic virus (ToMV) has the highest ability to cross protect against virulent ToMV among LuA and its derivatives and is stably inherited.
Growth, yield, fruit quality and symptom attenuation of inoculated tomato plants did not differ significantly between L11A-F and L11A. The infectivity of progeny viruses in tomato infected with LuA-F was less than 4% of that with virulent ToMV. From these
results, L11A-F appears to possess the properties necessary for practical use. To manage L11A-F strictly, a PCR-based assay to detect trace contamination of virulent ToMV in L11A-F preparations was established.
Received 10 June 2002/ Accepted in revised form 30 October 2002 相似文献
DAS-ELISA proved to be reliable enough to detect a latent infection by Tomato spotted wilt virus (TSWV) in asymptomatic stock plants of chrysanthemum. A high density of Frankliniella occidentalis, the predominant vector, in the presence of latently infected stock plants resulted in a high incidence of disease in the chrysanthemum
production field. The incidence of disease was low when the vector thrips were not abundant in spite of the presence of latently
infected stock plants. These results suggest that an infestation of the vector thrips causes severe secondary spread of TSWV
originating from latently infected stock plants in chrysanthemum production fields.
Received 27 July 2001/ Accepted in revised form 27 November 2001 相似文献
In March 1999, we found prairie gentian (Eustoma grandiflorum) infected with powdery mildew in a greenhouse in Oita Prefecture, Japan. Morphological observation revealed that the causal
fungus belongs to the mitosporic genus Oidium subgenus Pseudoidium [teleomorph: Erysiphe sensu Braun and Takamatsu (2000)]. Precise taxonomic position of the fungus, however, is uncertain due to lack of the perfect stage.
We determined the nucleotide sequence of the rDNA ITS region of the fungus. Comparison of the sequence with those obtained
from DNA databases of this fungal group revealed that the sequence is identical to those of powdery mildews from garden four-o'clock
(Mirabilis jalapa) and broad bean (Vicia faba). Inoculation of an isolate from garden four-o'clock caused mildew on prairie gentian and broad bean, suggesting that the
prairie gentian mildew originates from garden four-o'clock or broad bean. Molecular phylogenetic analysis indicated a close
relationship of this fungus to Erysiphe baeumleri on Vicia spp. and E. trifolii on Trifolium pratense. From these results, we propose that prairie gentian mildew diverged from a Fabaceae-parasitic ancestor.
Received 14 March 2002/ Accepted in revised form 28 May 2002 相似文献
