Fatal respiratory disease in Nilgiri tahr: possibly malignant catarrhal fever.

Nilgiri tahr (Hemitragus hylocrius) are native to India and are a rare zoo exhibit. This report describes an acute respiratory disease in tahr that caused the death of 15 of 16 animals in an extensive exhibit of about 35 acres where they were housed together with a variety of other exotic species of ruminants. The deaths occurred in two separate outbreaks and were associated with losses from malignant catarrhal fever in other ruminants in the exhibit. The most prominent clinical sign was severe dyspnea, and death occurred within five days. The principal lesions were an acute nonsuppurative inflammation of the respiratory tract and pulmonary vessels, lymphadenopathy and lymphoid cell infiltration in the organs of some animals. It was conjectured that the tahr died of a unique pneumonic form of malignant catarrhal fever. Attempts at viral isolation were negative.     

Antibody response and antigen-specific gamma-interferon profiles of vaccinated and unvaccinated pregnant sheep experimentally infected with Brucella melitensis

It is well known that the immune response in sheep against Brucella melitensis is subject to individual variation, depending on diverse factors. It bears asking whether these factors (e.g. clinical disease, active infection, state of previous immunity), when affecting a group, can cause variation in the performance of different diagnostic tests. To clarify some of the circumstances in which this immune response can vary, we examine the immune-response profile of sheep protected against the clinical disease by prior vaccination with strain Rev. 1 in comparison with the profile of unprotected females showing the classical brucellosis symptoms. An experimental infection was provoked at midpregnancy under controlled conditions of both non-vaccinated (n=7) and previously Rev.1-vaccinated ewes (n=5). Their immune response was monitored from 7 to 9 weeks before abortion or normal birth to 30 weeks afterwards. Antibody response was assessed by classical tests (Rose Bengal test, complement fixation test (CFT)) in comparison with other diagnostic tests (indirect ELISA (iELISA), competitive ELISA (cELISA), fluorescence polarization assay (FPA), immunocapture test (ICT)). In addition, the cell-mediated immune response was indirectly evaluated by the in vitro antigen-specific release of gamma-interferon. The antibody levels and antigen-specific gamma-IFN profile of the non-vaccinated ewes having the disease and excreting the pathogen was notably high and differed significantly (P<0.05 or P<0.01) from those of vaccinated ewes that neither contracted brucellosis nor excreted the pathogen. In general, all the tests detect the infection in the non-vaccinated ewes with substantial effectiveness. It can be concluded that the high levels of circulating antibodies and of antigen-specific gamma-IFN are related to active Brucella infection. Similarly, the state of protection against the disease, but not necessarily against infection, due to a previous immunization with the Rev. 1 vaccination, appears to be responsible for a low level of detectable immune response. Nevertheless, the design of the study limits conclusions to pregnant ewes and cannot be extrapolated to non-pregnant ewes or rams. Likewise, the study provides no information on animals which are carriers of B. melitensis.     

Identification of dynamic growth of Hedera helix as response to variation in daily light levels

Summary

The dynamic responses in shoot growth of three pot plants ofHedera helix L. ‘Mein Herz‘ in relation to changes in photosynthetic photon flux density (PPFD) is identified. In the experiment a two-level strategy of PPFD to the plants was used. The current level of PPFD on any day was either high or low, and was determined using a pseudo random binary signal (PRBS) both to avoid any correlations between the PPFD and other variables, and to ensure that the dynamic characteristics of the plant growth were present in the data. For each of the three pot plants a discrete dynamic model of growth responses to PPFD was estimated, and an agreement between the parameters of the three models was observed. The results show that not only is the current PPFD level of the current day related to the daily increase in fresh weight, but growth is also a function of the PPFD level of the previous days. With respect to the previous days the effects of PPFD can be described as an exponential decay where from one day to the previous day the effect of PPFD is reduced to 67%, 66% and 80% respectively for the three pot plants in the experiment.     

Propagation temperature,PPFD, auxin treatment,cutting size and cutting position affect root formation,axillary bud growth and shoot development in miniature rose (Rosa hybrida L.) plants and alter homogeneity

Summary

Rooting and growth responses of miniature rose cuttings were investigated in an experiment in which four propagation temperatures, two photosynthetic photon flux densities (PPFDs) with five auxin (IBA) concentrations, cutting sizes and cutting positions, were combined factorially in a response-surface design. Most prominently, temperature, cutting size and auxin and their interactions, influenced root and shoot growth. A propagation temperature of 24.6°C, and IBA concentrations between 10^–3 and 10^–1M, depending on temperature, were optimal for root formation. Root formation in extra short cuttings was delayed at low IBA concentrations. Regarding root formation, IBA could substitute for increased temperature as well as for increased cutting size. Onset of axillary bud growth was fastest at 24.6°C, and delayed in extra short cuttings. Application of IBA at 10^–4 to 10^–3M was optimal for axillary bud growth. By increasing the IBA concentration both time to flowering and plant height increased at 24.6°C. In cuttings from higher positions on stock plants, axillary shoots enhanced their growth to flowering, became shorter, and weighed less, suggesting occurrence of positional effects (topophysis). The growth rate increased with increasing IBA concentration, as well as from medial to low positioned cuttings. Increasing propagation PPFD from 46 to 72 µmol m^–2s^–1 did not affect the parameters. Time to axillary bud growth and time to first flower were related to time-to-visible root. Fast formation of roots apparently resulted in fast axillary bud growth. In time-to-visible root and axillary bud growth, the smallest variation between plants was found at optimal ranges for temperature, IBA concentration and cutting size, and further factors optimal for root formation and axillary bud growth provided the most synchronized plant development.     

In vitro shoot regeneration ofSolanum tuberosum cultivars: interactions of medium composition and leaf, leaflet, and explant position

Summary Shoot regeneration was investigated on explants from different leaves and leaflets of three potato cultivars Posmo, Folva and Oleva. Explants were excised from glasshouse grown plants and grown for 6 days on callus induction medium with indole-3-acetic acid or 2,4-dichlorophenoxyacetic acid. Explants were then transferred to auxin free shoot regeneration medium with gibberellic acid and 6-benzyladenine or zeatin. By using the optimum combinations and concentrations of plant growth regulators and by excision of explants from particular regions of proximal leaflets from newly unfolded leaves, shoot regeneration frequencies of 97.0% were obtained for cv. Posmo and 32.1% for cv. Folva. Shoot regeneration frequency of cv. Oleva was very low and could not be improved by the different treatments.     

Erwinia species in the lenticels of certified seed potatoes

Twelve-tuber samples were collected from 39 certified seed stocks grown in 4 states and a Canadian province. One-half of each sample was immersed in water and the other half exposed to a CO₂-N atmosphere at 25C to induce soft rot development at the lenticels. Pectolytic bacteria were isolated from 24 seed stocks which represented each producing area. The pathogenicity and biochemical reactions of 20 isolates were those ofErwinia carotovora var.atroseptica, except for one isolate which grew at 37C. Four isolates did not cause black leg but only three reacted biochemically likeE. carotovora var.carotovora. The results confirm reports that theErwinia spp. are tuber borne and that anaerobic conditions stimulate infection of naturally inoculated lenticels.     

A method for determination of the degree of gelatinization of starch

Summary An exactly weighed quantity of material to be analysed, corresponding to about 0.4 g starch, is hydrolized with α- and β-amylase as a catalyst. A corresponding quantity of the materil is boiled, cooled and then hydrolized with α- and β-amylase. The amounts of reducing carbohydrates produced, mainly maltose, are determined, and the relation between them is equivalent to the relation between the quantity of total starch and the quantity of gelatinized starch. A blank determination is done to give a correction for the reducing power of the enzymes and the raw material.

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Zusammenfassung Bei der Nerz-Fütterung mit Kartoffelmehl ist es für dessen Ausnützbarkeit sehr wichtig, dass die St?rke geliert ist. Die hier beschiebene analytische Methode erm?glicht eine genaue Bestimmung des Geliergrades. Das Prinzip ist, dass nur gelierte St?rke duch die Enzyme α- und β-Amylase hydrolysiert werden kann; der Reaktionsverlauf wird in Tabelle 2 gezeigt. Eine genau abgewogene Menge des zu analysierenden Materials, ungef?hr 0.4 g St?rke entsprechend, wird mit α- und β-Amylase als Katalysator hydrolysiert. Eine entsprechende Menge des Materials wird gekocht, gekühlt und dann mit α- et β-Amylase hydrolysiert. Die Menge der erzeugten reduzierenden Kohlehydrate, haupts?chlich Maltose, wird bestimmt, und das Verh?ltnis zwischen ihnen ist gleich dem Verh?ltnis zwischen der gesamten St?rkemenge und der Menge der gelierten St?rke. Eine Blindbestimmung wird vorgenommen, um eine Korrektur für die Reduzierf?higkeit der Enzyme und des Rohmaterials zu erm?glichen. Die Standard-Abweichungen einer Anzahl Analysen von Material mit bekanntem Geliergrad sind in Tabelle 3 angegeben.

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Résumé Quand la pomme de terre en poudre est utilisée dans l’alimentation des Martres il est très important que l’amidon soit gélatinisé. La méthode analytique ici décrite rend possible la détermination exacte du degré de gélatinisation. Le principe est que seul l’amidon gélatinisé peut être hydrolisé par les enzymes α- et β-amylase, dans le Tableau 2. On hydrolyse avec α- et β-amylase comme catalyseur une quantité de matière à analyser exactement pesée correspondant à environ 0,4 g d’amidon. Une quantité correspondante de matière est bouillie puis refroidie et ensuite hydrolysée avec α- et β-amylase. On détermine les quantités des hydrates de carbone réducteurs produits, principalement le maltose, le rapport de celles-ci est équivalent au rapport entre la quantité totale d’amidon et la quantité d’amidon gélatinité. On fait une détermination à blane pour apporter une correction en raison du pouvoir réducteur des enzymes et du matériel cru. Le Tableau 3 donne les déviations standards d’un certain nombre d’analyses de matière avec un degré connu de gélatinisation.

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Report no. 47 from the Research Institute of Commercial and Industrial Plants, Kolding, Denmark.