Clinical and immunologic response of cattle to administration of a vaccine containing modified-live bovine respiratory syncytial virus

Healthy yearling beef and dairy cattle were inoculated with a vaccine containing modified-live bovine respiratory syncytial virus (ML-BRSV), and sequential changes in clinical signs of disease, blood leukocyte subsets, BRSV-specific antibody titer, and in vitro lymphocyte blastogenic responses were monitored. Vaccination with ML-BRSV did not cause pyrexia, local or systemic hypersensitivity reaction, or respiratory tract disease. Episodes of leukopenia, abnormalities in lymphocyte subsets, or depression of phytomitogen-induced blastogenic responses were not observed subsequent to vaccination. Exposure to ML-BRSV resulted in at least a 16-fold increase in serum neutralizing antibody titer, with no increase seen in nonvaccinated contact controls. Significant BRSV-specific lymphocyte blastogenic responses were not detected, using one dose of several BRSV antigen preparations in a whole blood culturing system.     

Phenotypic comparison of ileal intraepithelial lymphocyte populations of suckling and weaned calves

Ileal intraepithelial lymphocyte (IEL) suspensions from suckling calves (1-3 weeks old) and weaned calves (3-6 months old) were phenotyped to determine whether there were differences in the lymphocyte populations consistent with postnatal maturation of the mucosal immune system. Flow cytometric comparisons of IEL from the two age groups revealed the presence of significantly larger proportions of CD4+ T lymphocytes and CD8+ T cells in the weaned animals. In contrast, there was a significantly larger proportion of B-B2+ IEL in the suckling calves. Freshly isolated IEL from both groups of calves expressed mRNA for TNF-alpha and IFN-gamma, but not IL-4 or IL-10. The B-B2+ IEL population was more closely examined by flow cytometry. These cells co-expressed IgM and CD21. However, they did not express IgA, IgG1, nor any of several additional leukocyte differentiation molecules. Immunohistochemical data confirmed the presence of IgM+ lymphocytes, and the paucity of IgA+ and IgG1+ lymphocytes in suckling calf ileum. However, substantial numbers of IgA+ and IgG1+ cells were observed in weaned calf ileum. Together, the data are consistent with ongoing postnatal maturation of the gut mucosal immune system.     

Commercial Seed Lots Exhibit Reduced Seed Dormancy in Comparison to Wild Seed Lots of Echinacea purpurea

Seed germination patterns were studied in E. purpurea (L.) Moench grouped by seed source, one group of seven lots from commercially cultivated populations and a second group of nine lots regenerated from ex situ conserved wild populations. Germination tests were conducted in a growth chamber in light (40 μmol·m(-2)·s(-1)) or darkness at 25 °C for 20 days after soaking the seeds in water for 10 minutes. Except for two seed lots from wild populations, better germination was observed for commercially cultivated populations in light (90% mean among seed lots, ranging from 82% to 95%) and in darkness (88% mean among seed lots, ranging from 82% to 97%) than for wild populations in light (56% mean among seed lots, ranging from 9% to 92%) or in darkness (37% mean among seed lots, ranging from 4% to 78%). No germination difference was measured between treatments in light and darkness in the commercially cultivated populations, but significant differences were noted for treatments among wild populations. These results suggest that repeated cycles of sowing seeds during cultivation without treatments for dormancy release resulted in reduced seed dormancy in E. purpurea.     

Habitat suitability and connectivity modeling reveal priority areas for Indiana bat (Myotis sodalis) conservation in a complex habitat mosaic

Context

Conservation for the Indiana bat (Myotis sodalis), a federally endangered species in the United States of America, is typically focused on local maternity sites; however, the species is a regional migrant, interacting with the environment at multiple spatial scales. Hierarchical levels of management may be necessary, but we have limited knowledge of landscape-level ecology, distribution, and connectivity of suitable areas in complex landscapes.

Objectives

We sought to (1) identify factors influencing M. sodalis maternity colony distribution in a mosaic landscape, (2) map suitable maternity habitat, and (3) quantify connectivity importance of patches to direct conservation action.

Methods

Using 3 decades of occurrence data, we tested a priori, hypothesis-driven habitat suitability models. We mapped suitable areas and quantified connectivity importance of habitat patches with probabilistic habitat availability metrics.

Results

Factors improving landscape-scale suitability included limited agriculture, more forest cover, forest edge, proximity to medium-sized water bodies, lower elevations, and limited urban development. Areas closer to hibernacula and rivers were suitable. Binary maps showed that 30% of the study area was suitable for M. sodalis and 29% was important for connectivity. Most suitable patches were important for intra-patch connectivity and far fewer contributed to inter-patch connectivity.

Conclusions

While simple models may be effective for small, homogenous landscapes, complex models are needed to explain habitat suitability in large, mixed landscapes. Suitability modeling identified factors that made sites attractive as maternity areas. Connectivity analysis improved our understanding of important areas for bats and prioritized areas to target for restoration.

     

Sulfometuron methyl influences seedling growth and leaf function of three conifer species

Seedling growth and gas exchange responses were measured for two potted seedling trials testing herbicide phytotoxicity to three important tree species of the Inland Northwest, USA. Media-filled pots were treated with sulfometuron methyl (Oust^?) in varying concentrations and planted with seedlings of Larix occidentalis Nutt., Pseudotsuga menziesii var. glauca (Beissn.) Franco, and Pinus monticola Dougl. ex D. Don. Seedlings were grown in two trials to determine the effects of two important residue breakdown factors, substrate moisture and pH, relative to that of herbicide application rate on seedling health. Changes in seedling height, root-collar diameter, and root volume were morphologic variables of interest, and physiological variables measured were net photosynthetic assimilation, stomatal conductance, and transpiration rate. While three levels of media moisture and four levels of media pH had no effect on seedling performance, most growth and leaf function variables were hindered across application rate treatments of all three species. Label-recommended dosages resulted in growth suppression levels potentially detrimental to seedling establishment for all three species. This was most pronounced for Pinus monticola, in particular for root growth, where untreated control seedlings showed 109% more root volume growth than treated seedlings. We conclude that when possible, a species-specific application rate might be found that balances the benefits of vegetation control with the phytotoxicity to promote optimal growth gains.     

Marked, biased, filter (MBF): use of digital X-radiography and mark-recapture to partition seed lots based on sampled individual seed quality attributes

We report results of preliminary evaluations of marked, biased, filter (MBF), a method for both estimating and improving the effectiveness of separating conifer seeds. MBF integrates elements of X-radiographic seed quality assessment and mark-recapture methods from wildlife population sampling. Given a sample drawn from a population, individual seeds with attributes targeted for separation are labelled with a mark which biases the subsequent removal probability of other, non-marked seeds in the lot during grading and processing, after returning the sample to the population. Bias in the marking filter, in the form of extra mass or density added to seeds, minimizes the likelihood that uncertainty due to sampling error in the prior estimate will result in empty seeds remaining in the population during processing. In two experiments, a ponderosa pine seed lot was partitioned into empty and filled fractions with an air column separator. Powder dye talc was used for marking in the first trial, with low bias (<1%) and a small sample size (n = 150) with dry (2% moisture content) and soaked (26% moisture content) seed lots. A second trial conducted with two coats of spray paint used for marking and a larger sample size (n = 400) resulted in removal of 100% of non-filled seeds in the population. A simulation was conducted to evaluate sample statistics upon which to base the value of threshold bias, τ, below which seeds in an X-rayed sample should be marked to achieve consistent separation. Estimating the marking threshold based on quantiles of filled seeds most consistently resulted in removal of the non-filled fraction. MBF is a useful method for statistically linking one or more individual seed quality attributes extracted from X-ray image analysis with population-level processing of seed lots.