Genetic diversity in blast resistance of Bhutan rice landraces

With an objective to evaluate the Bhutan rice (Oryza sativa L.) landraces for genetic diversity in blast resistance, 402 accessions viz. 352 landraces, a differential set of 32 R gene lines and 18 modern cultivars were field-evaluated in three blast ‘hotspot’ sites followed by genetic analysis of the 352 landraces with 27 microsatellite markers. Across the sites, 19 landraces (5.4%) exhibited complete resistance with zero disease score and 203 (58%) and 163 (46%) landraces showed high partial resistance for early leaf and panicle blast, respectively, with disease score of four to six. Field evaluation for leaf and panicle blast at three experimental sites in Bhutan showed best cultivar discrimination in early leaf blast at the tillering stage (heritability, h² = 0.32) and in the panicle blast at maturity (h² = 0.44). Subdivision of the genetic variation into cultivar groups revealed the most variation for blast severity within the 352 landraces with h² of 0.31 and 0.46 for early leaf and panicle blast, respectively. Cluster analysis of the landraces revealed two distinct rice cultivar groups, which separated at dissimilarity of 0.84 according to origin of the cultivars from low, mid and high altitude zones in Bhutan. All microsatellites were polymorphic with two to 21 different alleles per marker and a high polymorphic information content value of 0.61. The identified blast resistant landraces were genetically diverse originating from different rice cultivation zones. Further investigation of the resistant and partial resistant material may reveal specific blast resistance genes, which could be useful to mitigate blast incidence in rice-producing countries.     

Chronic hepatitis in Doberman pinschers. A review

Summary

Chronic hepatitis in Doberman pinschers is predominantly seen in female dogs, usually between 4 and 7 years of age and was first recognized in the early eighties. The histopathological characteristics of Doberman hepatitis are those of micronodular cirrhosis with histological features of fibrosis, piece meal necrosis and progressive lymphocyte and plasma cell infiltration of the portal triads. Currently there are two hypotheses on the pathogenesis although neither of them has been elucidated. The first hypothesis is that of a copper toxicosis. The second is that of autoimmunity. Similarities and differences with other breeds and studies on both hypotheses are reviewed, as well as results of recent research of our group. Based on recent findings chronic hepatitis in Doberman pinschers is most likely to be a form of copper toxicosis. Although there are several indications that suggest autoimmunity as well, this still remains unclear.     

The Impact of Tick Control on the Productivity of Indigenous Cattle under Ranch Conditions in Uganda

The impact of tick control on the productivity of indigenous cattle was investigated in three herds of East African shorthorn Zebu and Zebu×Ankole (Nganda) breeds, maintained under three tick management systems practised under ranch conditions: twice-a-week dipping, once-a-month dipping, and no tick control. The milk production and the growth rates of pre-weaned and post-weaned calves were monitored once a month over a period of 34 months. Milk offtake was 23% higher during the heavy rainy seasons than in the long dry seasons. Twice-a-week dipping increased the milk offtake by 21% in the second year of study and prolonged the duration of lactation in cows. Similarly, twice-a-week dipping increased the pre-weaning growth rate by 39% in the second year of study, but had no significant effect on the post-weaning growth rate. Generally, the growth rate of calves were greatest during the heavy rainy seasons and least during the long dry seasons. These results provide a basis for assessing the losses under different tick management systems in the various production systems.     

Transnasal endoscopic treatment of equine sinus disease in 14 clinical cases

Transnasal endoscopic sinus treatment was used in four horses diagnosed with primary sinusitis and 10 horses with dental sinusitis. Pre-existing (n = 5) or surgically created (n = 9) sinonasal fistulae were used as portals for transnasal endoscopic exploration, debridement and lavage of the inflamed sinus cavities. Endoscopic sinonasal fistulation was performed using either trans-endoscopic diode laser fibre (four cases) or an electrocautery instrument under endoscopic control (five cases). All procedures were performed on standing sedated horses with the use of local anaesthesia. In six cases, the ventral concha was fenestrated in order to gain a portal into the ventral conchal and rostral maxillary sinus. In two cases the dorsal concha was fenestrated to access the caudal group of the paranasal sinuses. One case required fenestration of the ventral conchal bulla due to its empyema. Post-operative bleeding was controlled with a nasal cavity tamponade for 24 h. Endoscopic lavage and debridement of the inflamed sinuses were performed every 2–3 days. Medical treatment consisted of antibiotic and anti-inflammatory drugs. In the cases of dental sinusitis, the underlying dental pathology was addressed. Median hospitalisation time was 10 days (range 5–25 days) and the median number of endoscopic procedures (including the initial procedure) was 4 (range 3–7). Cases were followed-up by telephone consultations with their owners. Intervals between discharge and last follow-up ranged from 4 to 22 months (median 9.5 months). Complete recovery was reported in 10 cases, clinical improvement (occasional nonpurulent discharge) in two cases. Two cases were readmitted due to recurrence of the purulent nasal discharge; both subsequently underwent trephination of the affected sinuses and made a full recovery after removal of the remaining pathological sinus content.     

Further identification of Hippeastrum Mosaic Virus

Infectious virus was isolated fromHippeastrum plants by density gradient centrifugation and examined with the electron microscope. The average lengths of the flexuous particles were 643±24 nm.Samenvatting Infectieus virus kon worden geïsoleerd uitHippeastrum-planten die mozaïekverschijnselen vertoonden, door middel van centrifugeren in een dichtheidsgradiënt. Het materiaal werd bekeken in een elektronenmicroscoop en gefotografeerd. De gemiddelde lengte van de buigzame staafies van hetHippeastrum-mozaïekvirus, berekend uit 600 metingen, bedraagt 643±24 nm.     

Untersuchungen zur Blattlausübertragbarkeit von Kartoffel-M-und-S-Virus

Zusammenfassung übertragungsversuche mitMyzus persicae vonSolanum demissum aufS. demissum zeigten, da? das Kartoffel-M-Virus dem nicht-persistenten übertragungstyp zugeordnet werden mu?, und zwar ?hnlich dem Kartoffel-Y-Virus, wie Parallel-versuche ergaben. Verschiedene M-Virusst?mme unterschieden sich dabei erheblich in ihrer übertragbarkeit. So konnten mit dem Stamm M 22 1 durchM. persicae 82% der Testpflanzen infiziert werden, mit dem Stamm D 1102 auf gleiche Weise jedoch nur etwa 1%. Andere M-Virusst?mme lagen dazwischen. Die Wirksamkeit einzelner Blattlausarten als übertr?ger war unterschiedlich. W?hrend mitM. persicae die besten übertragungserfolge erzielt wurden, fiel die Vektorleistung der anderen Arten in der Reihenfolge:Aphis frangulae, A. nasturtii undMacrosiphum solanifolii. 92 Kartoffelsorten wurden auf ihre Anf?lligkeit für den M-Virusstamm M 22 1 geprüft. Mehr als die H?lfte der getesteten Sorten waren bei gleichen Versuchsvoraussetzungen nicht oder nur sehr wenig dafür anf?llig, bei anderen wurden jedoch Infektionsraten bis zu 50% erzielt. Das Kartoffel-S-Virus galt bisher als nicht durch Blattl?use übertragbar. Es gelang jedoch, mitM. persicae bei 2 Gruppen von Isolaten dieses Virus auf 10–20% bzw. etwa 40% der Testpflanzen zu übertragen.

---

Summary The spread of potato virus M even in isolated seed crops indicates intensive vector transmission. Because of the ineffectiveness of systemic insecticides in the control of infection it appeared possible that the virus is transmissible after a somewhat short space of time and does not require a long period as could be inferred from previous work. Transmission experiments withMyzus persicae fromSolanum demissum toS. demissum gave even higher figures for infection with short than with long uptake periods. After fairly long uptake periods, between 15 min and 72 h, the transmission figure was often only about 10% (Fig. 1) so that, taking these uptake times in isolation, a semi-persistent method of transmission can be simulated. Parallel experiments with potato virus Y (strain Lü), however, gave similar results (Fig. 2) so that potato virus M must clearly be regarded as a non-persistent type. Different strains of virus M vary considerably in their aphid transmissibility. Whereas with strain M22 1 82% of test plants were infected by means ofM. persicae, with strain 8/6 the figure was 68%, with the strainAnett 34%, with the paracrinkle strain 13% and with strain D1102 only 1% (Fig. 3). Individual aphid species vary in their ability to transmit virus M.M. persicae is the most effective vector, other species show a diminishing potential in this order:Aphis frangulae, A. nasturtii andMacrosiphum solanifolii (Fig. 4). The susceptibility of 92 potato varieties was tested, usingM. persicae and the easily transmissible M22 1 strain of virus M. More than half of the varieties tested either failed to become infected or were infected in small numbers; the rest, however, showed infection up to 50% (Table 1). Potato virus S has hitherto been considered to be non-transmissible by aphids. However, in potato breeding stations some seedlings always become infected, which suggested the transmissibility by aphids of some strains of virus S. Transmission experiments confirmed this; various isolates of virus S were transmitted to 10–20% or 40% of the test plants byM. persicae (Fig. 5).

---

Résumé La propagation du virus M de la pomme de terre, même dans les régions isolées de production de plants, évoque une transmission intensive par des vecteurs. Etant donné l’inefficacité des insecticides systémiques pour endiguer la virose, il vient à la pensée que le virus est essentiellement transmissible après un délai court et non après un délai long, ainsi qu’il pouvait être conclu des recherches effectuées jusqu’à présent. Les recherches de transmission avecMyzus persicae deSolanum demissum àS. demissum révélaient également des cotes de transmission plus efficaces avec des temps de prélèvement courts plut?t que longs. Cependant avec des temps de prélèvements croissants, entre 15 min et 72 h, on trouve des cotes de transmission encore supérieures à 10% (Fig. 1), de sorte que, en considérant d’une manière isolée ces temps de prélèvement on pourrait croire erronément à un mode de transmission semi-persistant. Des recherches parallèles sur le virus Y de la Pomme de terre (souche Lü) donnaient cependant une situation similaire (Fig. 2) de sorte que le virus M de la pomme de terre doit indubitablement être considéré comme étant de type de transmission non persistant. Diverses souches de virus M se différencient beaucoup dans leurs possibilités de transmission par puceron. Alors qu’avec la souche M 221, 82% des plantes testées sont infectées parM. persicae, ce pourcentage est seulement de 68% avec la souche 8/6, de 34% avec la soucheAnett, de 13% avec la souche Paracrincle, et seulement de 1% avec la souche D 1102 (Fig. 3). Les espèces particulières de pucerons ne se prêtent pas dans la même mesure à la transmission du virus M.M. persicae se comporte comme vecteur pleinement efficace, les autres espèces montrent des pouvoirs vecteurs diminuant dans l’ordre:Aphis frangulae, A. nasturtii etMacrosiphum solanifolii (Fig. 4). 92 variétés de pomme de terre ont été testées pour leur sensibilité avecM. persicae et la souche de bonne transmission M 22 1. Plus de la moitié des variétés testées ne se laissent pas ou seulement dans une faible mesure infecter, chez d’autres cependant les taux d’infection atteignent jusqu’à 50% (Tableau 1). Le virus S de la Pomme de terre est considéré jusqu’à présent comme non transmis par aphide. Comme cependant dans les centres de recherches sur la pomme de terre, on ne voit de nouveau jamais des plantules de semis infectées par le virus S, on doit supposer une possibilité de transmission par pucerons d’une souche particulière de virus S. Des recherches de transmission confirment d’ailleurs que différents isolats de virus S se sont respectivement transmis à 10–20 ou 40% des plantes-tests (Fig. 5).

     

Selective disruption of gap junctional communication interferes with a patterning process in hydra

The cells that make up the body column of hydra are extensively joined by gap junctions, capable of mediating the rapid exchange of small hydrophilic molecules between the cytoplasms of neighboring cells. Both the rate of transfer of small molecules through the gap junctions and the rate of return of gap junction coupling after grafting experiments are sufficiently rapid to mediate events in the patterning of hydra tissue. Antibodies to the major rat liver gap junction protein (27,000 daltons) recognize a gap junction antigen in hydra and are effective in eliminating junctional communication between hydra cells. The antibodies perturb the head inhibition gradient in grafting operations, suggesting that cell-cell communication via gap junctions is important in this defined tissue patterning process.     

A comparison of four serological tests for the diagnosis of caseous lymphadenitis in sheep and goats

A double antibody sandwich ELISA (ELISA A) developed for the detection of Corynebacterium pseudotuberculosis infection in sheep and goats was modified to improve its sensitivity. To establish the sensitivity and specificity of this modified ELISA (ELISA B), sera from 183 sheep and 186 goats were tested using ELISAs A and B. Comparison was also made with two further ELISAs (C and D) developed in Australia that, respectively, detect antibodies to cell wall antigens or toxin.ELISA B had the best performance of the four tests. Its specificity was 98+/-1% for goats and 99+/-1% sheep. Its sensitivity was 94+/-3% for goats and 79+/-5% for sheep. ELISA B will now be tested for use in caseous lymphadenitis eradication and control programmes in The Netherlands. It will also be used in experimental studies of CL in Scotland.     

Chronic hepatitis in Doberman pinschers. A review

Chronic hepatitis in Doberman pinschers is predominantly seen in female dogs, usually between 4 and 7 years of age and was first recognized in the early eighties. The histopathological characteristics of Doberman hepatitis are those of micronodular cirrhosis with histological features of fibrosis, piece meal necrosis and progressive lymphocyte and plasma cell infiltration of the portal triads. Currently there are two hypotheses on the pathogenesis although neither of them has been elucidated. The first hypothesis is that of a copper toxicosis. The second is that of autoimmunity. Similarities and differences with other breeds and studies on both hypotheses are reviewed, as well as results of recent research of our group. Based on recent findings chronic hepatitis in Doberman pinschers is most likely to be a form of copper toxicosis. Although there are several indications that suggest autoimmunity as well, this still remains unclear.