Dissolution of Interlayers from Intergradient Soil Clays after Preheating at 400{degrees}C

Dehydroxylated interlayers have been removed from chlorite-vermiculite-montmorillonite intergrades by boiling the preheated sample in 0.5N NaOH for 2.5 minutes. Elements extracted can be conveniently analyzed spectrophotometrically. A convenient method of estimating the amount of elements present in interlayer positions and preparing the sample for analysis for expanding and nonexpanding mineral components is thus provided.     

Sampling to characterize landscape pattern

Current reseach suggests that metrics of landscape pattern may reflect ecological processes operating at different scales and may provide an appropriate indicator for monitoring regional ecological changes. This paper examines the extent to which a 1/16 areal subset of the landscape using equally spaced 40-km² hexagons can characterize the spatial extent of land cover types and landscape pattern (number of types of edges, patch shape complexity, dominance, and contagion). For 200-m resolution data the hexagon subset gives a reasonable estimate of overall landscape cover but may not be adequate for monitoring uncommon land cover types such as wetlands. For agriculture and forest, their proportion of the full landscape units is only outside the 95% confidence interval of the hexagon estimate 4–8% of the time, whereas the proportions for wetland and barren areas are outside the confidence interval 11–34% of the time. The hexagon subset also does not appear to be adequate as the sole basis for monitoring landscape pattern. The values for contagion, dominance, and shape complexity calculated on the full landscape units are outside the 95% confidence interval of the hexagon estimate 27–76% of the time. Other statistical analyses include regressions between full landscape and hexagon subsets, mean differences and standard errors along with tests on number of positive and negative values, and percent relative error of hexagon estimates.Although the research described in this article has been funded in part by the U.S. Environmental Protection Agency, under Interagency Agreement DW89934921-01-0 with the U.S. Department of Energy under Contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc., it has not been subjected to Agency review. Therefore, it does not necessarily reflect the views of the Agency. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.Research supported by the Landscape Characterization Project, Environmental Monitoring and Assessment Program, U.S. Environmental Protection Agency, under Interagency Agreement DW89934921-01-0 with the U.S. Department of Energy under Contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc., Environmental Sciences Division Publication No. 4090.     

Evidence of multiple anthelmintic resistance in a strain of Teladorsagia circumcincta (Ostertagia circumcincta) isolated from goats in Scotland

The efficacy of ivermectin, fenbendazole and levamisole was determined in lambs individually infected with 5000 third stage larvae of Teladorsagia (Ostertagia) species isolated from a herd of goats with a history of benzimidazole resistance and where the efficacy of ivermectin had also suffered an apparent decline. Efficacies, calculated using geometric means, for groups where treatments were directed against adult worms were 90.3 per cent (ivermectin), 43.4 per cent (fenbendazole) and 100 per cent (levamisole). The efficacy of ivermectin against immature stages was 83.2 per cent. Ivermectin was highly effective (99.9 per cent) against a known susceptible ovine strain of Teladorsagia.     

Bovine granulocyte/macrophage and erythroid colony culture: characteristics of the colonies and the assay systems.

Bovine bone marrow granulocyte/macrophage colonies were cultured in vitro in methyl cellulose and in plasma clots using bovine endotoxin-stimulated serum as a source of colony stimulating activity. The endotoxin-stimulated serum was four times as potent as the control serum in the methyl cellulose cultures. No significant increase in the number of colony forming units was observed when bovine marrow cells were maintained in suspension cultures for various periods prior to plating in methyl cellulose. The percentage of glass/plastic adherent cells in bovine marrow cells was observed to be 43% +/- 12 (SD). Benzidine positive erythroid colonies appeared in plasma clot cultures on day 4 and disappeared by day 9. No second population of erythroid colonies appeared either as a function of time or as a function of erythropoietin concentration. The optimum erythropoietin concentration for bovine erythroid cultures was found to be 1.0 unit/mL. A significant difference was observed between animals in their marrow capacity to produce erythroid colonies in culture but no significant difference was observed within individual animals over a period of three months.     

Formulation of Bacillus spp. for Biological Control of Plant Diseases

ABSTRACT Maximizing the potential for successfully developing and deploying a biocontrol product begins with a carefully crafted microbial screening procedure, proceeds with developing mass production protocols that optimize product quantity and quality, and ends with devising a product formulation that preserves shelf-life, aids product delivery, and enhances bioactivity. Microbial selection procedures that require prospective bio-control agents to possess both efficacy and amenability to production in liquid culture increase the likelihood of selecting agents with enhanced commercial development potential. Scale-up of biomass production procedures must optimize product quantity without compromise of product efficacy or amenability to stabilization and formulation. Formulation of Bacillus spp. for use against plant pathogens is an enormous topic in general terms but limited in published specifics regarding formulations used in commercially available products. Types of formulations include dry products such as wettable powders, dusts, and granules, and liquid products including cell suspensions in water, oils, and emulsions. Cells can also be microencapsulated. Considerations critical to designing successful formulations of microbial biomass are many fold and include preserving biomass viability during stabilization, drying, and rehydration; aiding biomass delivery, target coverage, and target adhesion; and enhancing biomass survival and efficacy after delivery to the target. Solutions to these formulation considerations will not necessarily be compatible. Data from several biocontrol systems including the use of B. subtilis OH 131.1 (NRRL B-30212) to reduce Fusarium head blight of wheat are used to illustrate many of these issues. Using our recently described assay for efficiently evaluating biomass production and formulation protocols, we demonstrate the effectiveness, in vitro, of UV protectant compounds lignin (PC 1307) and Blankophor BBH in reducing OH 131.1 morbidity when cells were exposed to UV light from artificial sunlight.     

Studies using Teladorsagia circumcincta in an in vitro direct challenge method using abomasal tissue explants

An in vitro direct challenge (IVDC) method in which abomasal tissue explants maintained at 37 degrees C in Hanks/Hepes solution (pH 7.6) in a high oxygen concentration (incubator gassed with pure oxygen and sealed prior to use) were-challenged with exsheathed third stage larvae of Teladorsagia circumcincta has been used to investigate the tissue association phase of larval establishment. Studies using na?ve and recently challenged immune sheep and goat abomasal tissues have shown significant reductions (P < 0.05) in the numbers of tissue associated larvae in material from immune animals. The mechanisms that affect the tissue association process appear to be labile since more larvae were recovered from the tissue digests of previously infected sheep that had not been recently exposed to larval challenge in comparison to those that had been recently challenged (P < 0.05). The method has also been used to demonstrate the influence of protein nutrition on the establishment of larvae in abomasal tissues and region specific differences in the efficacy of exclusion mechanisms. The technique appears to have potential as a means of investigating the crucial first phase of the process of establishment.