Yolk is the primary source of calcium for embryonic growth and development for most squamates, irrespective of mode of parity. The calcified eggshell is a secondary source for embryonic calcium in all oviparous eggs, but this structure is lost in viviparous lineages. Virginia striatula is a viviparous snake in which embryos obtain calcium from both yolk and placental transport of uterine calcium secretions. The developmental pattern of embryonic calcium acquisition in V. striatula is similar to that for oviparous snakes. Calbindin-D28K is a marker for epithelial calcium transport activity and plasma membrane Ca2+-ATPase (PMCA) provides the energy to catalyze the final step in calcium transport. Expression of calbindin-D28K and PMCA was measured by immunoblotting in yolk sac splanchnopleure and chorioallantois of a developmental series of V. striatula to test the hypothesis that these proteins mediate calcium transport to embryos. In addition, we compared the expression of calbindin-D28K in extraembryonic membranes of V. striatula throughout development to a previously published expression pattern in an oviparous snake to test the hypothesis that the ontogeny of calcium transport function is independent of reproductive mode. Expression of calbindin-D28K increased in yolk sac splanchnopleure and chorioallantois coincident with calcium mobilization from yolk and uterine sources and with embryonic growth. The amount of PMCA in the chorioallantois did not change through development suggesting its expression is not rate limiting for calcium transport. The pattern of expression of calbindin-D28K and PMCA confirms our initial hypothesis that these proteins mediate embryonic calcium uptake. In addition, the developmental pattern of calbindin-D28K expression in V. striatula is similar to that of an oviparous snake, which suggests that calcium transport mechanisms and their regulation are independent of reproductive mode.

The yolk splanchnopleure and chorioallantoic membrane of oviparous reptiles transport calcium from the yolk and eggshell to the developing embryo. Among oviparous amniotes, the mechanism of calcium mobilization to embryos has been studied only in domestic fowl, in which the mechanism of calcium transport of the yolk splanchnopleure differs from the chorioallantoic membrane. Transport of calcium is facilitated by calbindin-D28K in endodermal cells of the yolk splanchnopleure of chickens but the chorioallantoic membrane does not express calbindin-D28K. We used immunoblotting to assay for calbindin-D28K expression in yolk splanchnopleure and chorioallantoic membrane of the corn snake, Elaphe guttata, to test the hypothesis that the mechanism of calcium transport by extraembryonic membranes of snakes is similar to birds. High calbindin-D28K expression was detected in samples of yolk splanchnopleure and chorioallantoic membrane during late embryonic stages. We conclude that calbindin-D28K is expressed in these extraembryonic membranes to facilitate transport of calcium and that the mechanism of calcium transport of the chorioallantoic membrane of the corn snake differs from that of the chicken. Further, we conclude that calbindin-D28K expression is developmentally regulated and increases during later embryonic stages in the corn snake.

Nutrient loading is negatively affecting South Africa’s freshwater resources and ecosystems. Anthropogenic activities are the leading causes of continuous nutrient loading in the country’s water resources. This study examines the dynamics of nutrient loading in the Vaal River. The objectives are to explore nutrient loading in the Vaal River over the past two decades and to compare the differences between the two decades. Water quality data were obtained from the Department of Water and Sanitation (DWS) Water Resource Quality Information Services (RQIS) database. Elevated nutrients of NH4+, N03, P04 3- and chlorophyll-a were observed at selected sites at various times during the 20 year period under analysis. Nutrients concentration are elevated alongside agricultural and industrial activities, and urban areas. Student t-tests investigated the difference between the two decades and in most cases showed significant differences between these decades. The last decade showed elevated nutrient levels for N03, NH4+ and chlorophyll-a in most of the DWS monitoring sites. Only P04 3- at some sites showed a reduction from the previous decade. The study concludes that upper and middle sections of Vaal River are eutrophic and hypertrophic and a trend toward a permanent state of these conditions is likely without a long-term solution to address the problem of excessive nutrient loading entering the Vaal River system.

The choice of plant materials is an important factor in restoration or revegetation of disturbed rangelands. To better identify plant materials that could be adapted to increased competition from invasive grasses and fluctuations in temperature and precipitation, there is a need to understand potential seedling establishment, plant persistence, and dry-matter yield (DMY) as a measure of plant vigor in the newly developed varieties across a wide range of environmental conditions. Experiments were conducted on four semiarid range sites to compare these traits in 14 perennial cool-season grass species currently used for revegetation in the Western U.S.A. There were location differences, with overall seedling establishment ranging from 28 to 70% seedling frequency at Malta, ID and Tintic, UT sites, respectively. No one species was statistically highest for seedling frequency at all four locations. However, there were four species that had higher seedling frequency at three of the four locations: Siberian wheatgrass (Agropyron fragile [Roth] Candargy), crested wheatgrass (Agropyron cristatum [L.] Gaertn), and (Agropyron desertorum [Fish. ex Link] J. A. Schultes), intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth & D.R. Dewey) and Snake River wheatgrass (Elymus wawawaiensis J. Carlson & Barkworth). The newer varieties, in most instances, had increased seedling frequency vs. older varieties. Intermediate wheatgrass had the highest dry matter yields (DMY) at the Beaver location while crested and Siberian wheatgrass were highest for DMY at the Cheyenne location. Plant frequency was evaluated every year for five years after planting to determine stand persistence. Trends in plant persistence showed that, although difficult to establish, stands of western wheatgrass increased in the years after establishment due to rhizome development. Slender wheatgrass had a negative linear trend in stand persistence at the four tested locations. These results can help land managers make informed decisions concerning the choice of plant materials for revegetation projects, as related to potential seedling establishment, stand persistence, and relative biomass production.

Grazing is a primary land use in much of the western United States, but little is known about grazing impacts on water quality. The most sensitive water quality indicators of grazing are the fecal indicator bacteria. The objective of this study was to develop a general transport model describing the movement of fecal indicator bacteria from upland sources to channel systems. Model development was done using simulated rainfall and a runoff surface 30.48 m by 1.83 m. Initially the runoff surface was smooth concrete and was used to examine the effects of distance from the outlet on coliform counts by locating fecal material at various distances for five replications. Afterwards, the surface was covered by clay soil. Total and fecal coliforms were determined by the multiple-tube method. Overland flow was described by the kinematic wave equations. Bacterial transport was modeled with a random ordinary differential equation. Initial conditions and assumptions allowed solution for the probability density function (pdf), means, and variances. The pdf at the slope outlet was found to be normal for the assumed conditions. Solutions for the means and variances were different because initial conditions differed for the relationship between equilibrium and travel time. Three parameters were fitted, a mean retention and two variance terms. The retention parameter appeared to be constant for all cases. The variance terms were obtained only for the rising hydrograph. For the concrete surface, comparison of predicted and observed means and variances indicated poor fits during initial stages of simulation. Observed values attained steady state rapidly. There was no replication on the soil surface, and an initial run found high background counts. Background counts were considered to be constant and incorporated into the mean equation. A numerical solution to the mean equation was required because of the unsteady rainfall excess. The background counts and clay content of the soil prevented detection of impacts from a single source.

Chikungunya (CHIK) is an emerging viral disease, which causes significant morbidity and mortality throughout tropical/subtropical areas of the world, including a recent outbreak in the Americas. Disease typically includes fever, rash, and arthritis. Joint involvement is generally self-limiting, but infection with Chikungunya virus (CHIKV) can lead to chronic debilitating arthritis that can last for months to years. With no vaccine and no licensed treatment, suitable animal models of CHIKV are needed to test intervention strategies. We developed a model of CHIK in DBA1/J mice that develop joint swelling, increase in inflammatory cytokines and splenomegaly in mice, which include important symptoms of disease seen in infected humans. We used this model to test the hypothesis that treatment with immune-modulatory compounds would ameliorate disease. GP1681, which suppresses TNF-α, IL-1β, and IL-6, exacerbated CHIK as indicated by increased footpad swelling and viral load. Prophylactic treatment with mDEF201, an adenovirus-vectored interferon, reduced disease, including joint swelling, virus titers at the site of virus challenge and inflammatory cytokines (IL-6, MCP-1, MIP-1α, and RANTES), although efficacy waned as treatment initiation was extended beyond virus challenge. Methotrexate treatment was also effective at ameliorating joint swelling and other disease parameters. Actemra (ACT), an anti-IL-6 antibody, reduced IL-6 levels to baseline, although the resulting improvement in footpad swelling was not significant. Combination therapy with methotrexate and ACT resulted in reduced footpad swelling. Based on our results, immune modulators have potential for the treatment of CHIKV and some of the compounds tested might have potential for clinical developmental.

The production of forage seed for use in the eastern United States is a large industry in Utah and other Western States. The development or forage synthetics in the east with production or seed in the west raises the questions “Is there a change in the synthetic when seed is produced under different environmental conditions?” To obtain information relating to genetic stability of grass and legume seed crops produced under various environmental conditions, the USDA-ARS Crops Research Division, Forage and Range Research Branch, Foundation Seed Production Section, set up several experimental plots in the western United States. These are located in Washington, Utah, Texas, and California.

No description available.

No description available.

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