Detection of Spongospora subterranea using monoclonal antibodies in ELISA

Five hybridoma cell lines secreting antibodies (MAbs) recognizing zoospores of S. subterranea were raised from splenocytes of mice. One MAb also weakly recognized plasmodia/zoosporangia and cystosori of S. subterranea , and another recognized only plasmodia/zoosporangia in plate-trapped antigen ELISA. Polymyxa graminis was recognized most strongly out of 26 micro-organisms other than S. subterranea against which the MAbs were tested. Most were recognized only weakly or not at all. The MAb that recognized zoospores of S. subterranea most strongly detected as few as three zoospores per microtitre plate well when 12 replicate wells per treatment were arranged randomly on plates and absorbance values subjected to analysis of variance. The sensitivity of detection was not improved by mixing antibodies, using a biotin-streptavidin amplification system, or by using a double antibody sandwich system. Zoospores of S. subterranea flushed from soil were detected only after unrealistically large numbers of cystosori had been added. They were not detected in samples of naturally infested soil removed from a field shortly after a severely scabbed potato crop had been harvested.     

Variations in the Growth of Different Seeds of Acer pseudoplatanus and Betula verrucosa Grown on Different Soils

Seed of Acer pseudoplatanus was obtained from six widely scatteredlocations in Europe, and seedlings from these seed-sources weregrown on 25 different soils, covering a wide range of soil properties.Seedlings from four seed-sources of Betula verrucosa were alsogrown. There was a very wide variation in growth on the differentsoils, and between the two species; but relatively little variationbetween seed-lots within a species, and no significant interactionbetween seed-lot and soil, over the 2-year period of the experiment.It is concluded, therefore, that any one of the seed-lots usedin this experiment could have been used to assess the responseof seedlings of that species to changes in soil type, and thatvariation in growth due to genetic differences within thesespecies is likely to be small in comparison to the variationdue to soil conditions.     

Pharmacokinetics of fenbendazole in dogs

Fenbendazole was administered to dogs at a dose rate of 20 mg/kg body weight on a single occasion in gelatin capsules, on 5 consecutive days in feed, and on a single occasion as an alginate suspension. It was also administered at a dose rate of 100 mg/kg body weight on a single occasion in feed. Following single administration of 20 mg/kg fenbendazole mean maximum concentrations (Cmax) of the parent drug and its known active sulphoxide metabolite were 0.42 +/- 0.05 and 0.31 +/- 0.05 microgram/ml, respectively. Mean times until maximum concentrations were achieved (tmax) were 12.67 +/- 4.18 and 15.33 +/- 2.81 h, respectively, and areas under the plasma concentration-time curves (AUC) were 5.83 +/- 0.65 and 4.60 +/- 0.57 microgram.h/ml, respectively. Administration in feed increased the apparent bioavailability and administration for 5 consecutive days provided sustained plasma concentrations, generally greater than 0.2 microgram/ml. Administration as an alginate did not increase bioavailability or extend the persistence in plasma. It did increase the tmax to 16.80 +/- 2.93 and 20.00 +/- 2.53 h for fenbendazole and its sulphoxide metabolite, respectively. Increasing the dose from 20 mg/kg to 100 mg/kg did not substantially increase the Cmax or AUC.     

Evaluating Alternative Regional Planning Models

The REMI and IMPLAN models are widely used approaches to estimating economic impacts for small regions. However, few benchmarks exist for assessing these estimates. This paper evaluates the relative performance of these models in terms of a given impact: the opening of an automobile assembly plant in central Illinois. Although our results are not conclusive and are limited by our application, we find that in terms of several indirect performance criteria, IMPLAN's outcomes, on balance, are somewhat more plausible than those for REMI.     

Organic matter retention in an upland humic podzol; the effects of pH and solute type

This paper discusses the effects of different horizons and soil solution compositions on dissolved organic matter retention in a moorland podzol and compares the results with previous studies of forest podzols. Adsorption isotherms were constructed for each of the major horizons of a freely draining, upland, moorland, humic podzol from north-east Scotland, to investigate processes of retention and release of dissolved organic matter (DOM). Carbon retention of a range of solute types was studied, and phthalate was chosen as a model compound to measure carbon retention at three different pH values (3, 4.5 and 6). Retention and release of DOM was related to chemical, physical and mineralogical characteristics of the different soil horizons. All the mineral horizons retained DOM, with the Bs horizon most retentive. Solution pH did not significantly affect DOM retention in the O and A horizons. At pH 3 and 4.5 organic matter was weakly retained in the Bhs horizon, but strongly retained in the Bs and the Cx horizons. At pH 6 reversal of surface charge occurred in the Bs and Cx horizons resulting in the release of similar amounts of organic matter to that released from the O horizon at the same pH. The results demonstrate how podzols act as a ‘valve’ in controlling the input of dissolved organic compounds into surface and ground water, and how sensitive the controlling mechanisms are to pH change.