The effects of recombinant LHRH fusion proteins on testicular development and histology in ram lambs.

Two recombinant luteinizing hormone releasing hormone (LHRH) fusion proteins were evaluated for their effectiveness in suppression of testicular development and histology by injecting together. Recombinant fusion proteins, ovalbumin-LHRH-7 and thioredoxin-LHRH-7, were generated using recombinant DNA technology and expressed in E. Coli. Eleven ram lambs ranked by age and body weight were randomly assigned to receive either ovalbumin and thioredoxin recombinant protein mixture (control group, n = 5) or ovalbumin-LHRH-7 and thioredoxin-LHRH-7 recombinant fusion protein mixture, anti-LHRH vaccine, (immunization group, n = 6). Animals in each group were weaned at 17 wk of age and were injected (primary immunization) with either mixture at 18 wk of age. Both groups received a booster immunization 8 wks later (26 wk of age). Scrotal circumference, scrotal length, testicular diameter and testicular length were measured in both groups every other week. All animals were slaughtered at 36 wk of age. Immediately after slaughter, a small testicular tissue was taken and processed for histological examination. In the ram lambs in immunization group scrotal circumference and testicular diameter increased steadily until second booster and then remained as a plateau until the end of the experiment. The differences in scrotal circumferences and testicular diameter were significant between the two groups during the last three weeks of the study (p < 0.05). There were no differences in testicular and scrotal length throughout the study (p > 0.05). Seminiferous tubules lost their regular shape and were decreased in diameter in immunization group. Although a few spermatozoa were seen in some tubules, in general, there were atrophy of the seminiferous tubules and loss of spermatogenesis, nevertheless, it seemed that animals in this group were potentially fertile.     

The present status of “quick tests” for on-farm analysis with emphasis on manures and soil: What is available and what is lacking?

There is an increasing interest in on-farm testing of a variety of materials, from soils to materials produced or utilized on the farm, including manure. Among the issues to consider are selection of constituents of interest, e.g., fiber and protein in forages versus inorganic-and organic-N and P in manures; the nature of the testing, e.g., conventionally based assays using solutions or test strips versus portable instruments; the potential advantages or disadvantages of on-farm versus conventional laboratory testing, such as speed, timeliness, waste generation, and cost. The availability of on-farm testing methods varies greatly with both the media in question and the analyte of interest. For example, for manures several quick tests exist for the determination of total ammoniacal N (TAN) which can be quite accurate (R² of .9 or better versus laboratory determinations), fast and reasonably inexpensive, while no such methods exist for the determination of organic-N in the same samples. No quick test has been found satisfactory for the determination of P or K in dairy or poultry manures, although excellent results have been obtained for swine manure. Similarly, soil test kits have existed for years for determining N, P and K, but no such test exists for determining soil C content (organic or inorganic), and no inexpensive method exists for forage quality determinations (fiber, protein, digestibility). Spectroscopic methods such as near-and mid-infrared spectroscopy have found increasing use in the laboratory for the rapid analysis of a wide variety of products including feeds, manures and soils and offer great potential for on-farm determinations. This paper discusses the present state, and future potential, of methods suitable for on-farm testing of the wide variety of materials from soils to those materials utilized or produced on a farm, with emphasis on manures and soils and spectroscopic methods.     

Wildlife–livestock interactions in a western rangeland setting: Quantifying disease-relevant contacts

Disease transmission between wild ungulates and domestic livestock is an important and challenging animal health issue. The potential for disease transmission between wildlife and livestock is notoriously difficult to estimate. The first step for estimating the potential for between-species disease transmission is to quantify proximity between individuals of different species in space and time. This study estimates second-order statistics of spatio-temporal location data from radio-collared free-ranging deer, elk and cattle in northeast Oregon. Our results indicate, that when observed simultaneously, elk and cattle occur in closer proximity to each other than what would be expected based on general space use of these species. The same is true for deer and elk but not for deer and cattle. Our analysis also demonstrates that average distances between cattle and elk are largely driven by rare events of close co-mingling between the species, which extend over several hours. Behavioral causes for these co-mingling events are currently unknown. Understanding the causes for such events will be important for designing grazing practices that minimize wildlife–livestock contacts.     

Calcium channels in planar lipid bilayers: insights into mechanisms of ion permeation and gating

Electrophysiological recordings were used to analyze single calcium channels in planar lipid bilayers after membranes from bovine cardiac sarcolemmal vesicles had been incorporated into the bilayer. In these cell-free conditions, channels in the bilayer showed unitary barium or calcium conductances, gating kinetics, and pharmacological responses that were similar to dihydropyridine-sensitive calcium channels in intact cells. The open channel current varied in a nonlinear manner with voltage under asymmetric (that is, physiological) ionic conditions. However, with identical solutions on both sides of the bilayer, the current-voltage relation was linear. In matched experiments, calcium channels from skeletal muscle T-tubules differed significantly from cardiac calcium channels in their conductance properties and gating kinetics.     

Crystallization at Inorganic-organic Interfaces: Biominerals and Biomimetic Synthesis

Crystallization is an important process in a wide range of scientific disciplines including chemistry, physics, biology, geology, and materials science. Recent investigations of biomineralization indicate that specific molecular interactions at inorganic-organic interfaces can result in the controlled nucleation and growth of inorganic crystals. Synthetic systems have highlighted the importance of electrostatic binding or association, geometric matching (epitaxis), and stereochemical correspondence in these recognition processes. Similarly, organic molecules in solution can influence the morphology of inorganic crystals if there is molecular complementarity at the crystal-additive interface. A biomimetic approach based on these principles could lead to the development of new strategies in the controlled synthesis of inorganic nanophases, the crystal engineering of bulk solids, and the assembly of organized composite and ceramic materials.