Perception of Grazing to Promote Ecological Services in Recreational and Government Contracted Grasslands

Managed grazing in grasslands not currently grazed such as those enrolled in the Conservation Reserve Program or used for recreational activities has the potential to improve plant community diversity and soil quality thus enhancing many grassland ecological services including wildlife habitat, carbon sequestration, and preserving water quality. Grazing in grasslands not currently grazed increases the available forage for grazing cattle to reduce the pressure on current pasturelands. However, introducing managed grazing into grasslands not currently grazed poses unique challenges including repairing or installing infrastructure, movement of cattle to new grazing areas, and developing agreements to ensure grazing management meets the goals of both the land owner and cattle producer. To determine the potential for integration of managed grazing into perennial grassland landscapes, a survey was made available to cattle producers and grassland owners throughout the Midwest. Results from 65 respondents throughout the Midwest indicate grassland owners and cattle producers recognize that grazing has potential to enhance the ecological value of grasslands; however, a majority of cattle producers (53%) feel grassland owners don’t want to allow grazing on their land. Of the grassland owners surveyed, 63% wanted to attract wildlife for hunting and 87% would allow short duration grazing to enhance wildlife habitat. If grazing was allowed on government contracted grasslands, 79% of cattle producers were willing to move cattle up to 10 miles for less than 45 days of grazing. Both grassland owners and cattle producers in the survey were most likely to install infrastructure when grazing contracts lasted at least 5 years. The results of this survey indicate both cattle producers and grassland owners are willing to graze grasslands not currently grazed; however, payments would be required by more than 70% of grassland owners to compensate for lost government payments or at a rate equal to current pasture rent

Quantitative Assessment of the Risk of Release of Foot-and-Mouth Disease Virus via Export of Bull Semen from Israel

Various foot-and-mouth disease (FMD) virus strains circulate in the Middle East, causing frequent episodes of FMD outbreaks among Israeli livestock. Since the virus is highly resistant in semen, artificial insemination with contaminated bull semen may lead to the infection of the receiver cow. As a non-FMD-free country with vaccination, Israel is currently engaged in trading bull semen only with countries of the same status. The purpose of this study was to assess the risk of release of FMD virus through export of bull semen in order to estimate the risk for FMD-free countries considering purchasing Israeli bull semen. A stochastic risk assessment model was used to estimate this risk, defined as the annual likelihood of exporting at least one ejaculate of bull semen contaminated with viable FMD virus. A total of 45 scenarios were assessed to account for uncertainty and variability around specific parameter estimates and to evaluate the effect of various mitigation measures, such as performing a preexport test on semen ejaculates. Under the most plausible scenario, the annual likelihood of exporting bull semen contaminated with FMD virus had a median of 1.3 * 10(-7) for an export of 100 ejaculates per year. This corresponds to one infected ejaculate exported every 7 million years. Under the worst-case scenario, the median of the risk rose to 7.9 * 10(-5), which is equivalent to the export of one infected ejaculate every 12,000 years. Sensitivity analysis indicated that the most influential parameter is the probability of viral excretion in infected bulls

To understand muscle you must take it apartle

Striated muscle is an elegant system for study at many levels. Much has been learned about the mechanism of contraction from studying the mechanical properties of intact and permeabilized (or skinned) muscle fibers. Structural studies using electron microscopy, X-ray diffraction or spectroscopic probes attached to various contractile proteins were possible because of the highly ordered sarcomeric arrangement of actin and myosin. However, to understand the mechanism of force generation at a molecular level, it is necessary to take the system apart and study the interaction of myosin with actin using in vitro assays. This reductionist approach has lead to many fundamental insights into how myosin powers muscle contraction. In addition, nature has provided scientists with an array of muscles with different mechanical properties and with a superfamily of myosin molecules. Taking advantage of this diversity in myosin structure and function has lead to additional insights into common properties of force generation. This review will highlight the development of the major assays and methods that have allowed this combined reductionist and comparative approach to be so fruitful. This review highlights the history of biochemical and biophysical studies of myosin and demonstrates how a broad comparative approach combined with reductionist studies have led to a detailed understanding of how myosin interacts with actin and uses chemical energy to generate force and movement in muscle contraction and motility in general

Enhancing Botanical Composition and Wildlife Habitat of Pastures in South Central Iowa through Soil Disturbance by Mob-grazing of Beef Cattle

South central Iowa grasslands are dominated by cool season grass species with low productivity and little plant diversity which limits the forage yield and quality for grazing animals and habitat for native grassland wildlife. Strategic spring mob-grazing may reduce competition from cool-season grass species allowing early successional species, legumes, and native plants to establish while improving soil characteristics. Two blocks of three replicated pastures were divided into 5 equal-sized paddocks to determine the effects of early spring mob-grazing on pasture forage and soil characteristics. In each pasture, one paddock was not grazed (NG) and 4 were strip- (S; moved once per day with a back fence) or mob- (M; moved 4 times per day with a back fence) grazed beginning in May of 2011 (BL1) and 2012 (BL2) by 10 cows at a live forage DM allowance of 2% BW/d. Subsequently, one mob (MR) and strip (SR) paddock in each pasture was rotationally stocked to remove 50% of the live forage with 35-d rest periods beginning 60 d after spring grazing in yr 1 of each block. Measurements included pasture botanical composition determined by the line transect method, soil penetration resistance determined with a penetrometer, water infiltration determined with double ring infiltrometers, soil bulk density, and ground nesting bird habitat measured as visual obstruction to a 3.3x 3.3 ft board by image analysis of digital photos. In BL1 and BL2 after mob- or strip- grazing, the proportion of bare ground was greater (P\u3c 0.05) in rotationally grazed paddocks than NG paddocks in most months. The proportion of annual grasses was greater (P\u3c 0.05) in grazed than NG paddocks in July 2011 in BL1. In 2012, the proportion of legumes was greater (P\u3c 0.05) than NG paddocks in M, MR, and SR paddocks in May, M and SR paddocks in July, and all grazed paddocks in BL 1 in October. But in 2013, the proportion of legumes was greater in MR and S paddocks in May and MR paddocks in October than NG paddocks. The proportion of warm season grasses in BL2 was less (P\u3c 0.05) in MR and SR paddocks than NG and M paddocks in August 2013. In BL1, penetration resistance was greater (P\u3c 0.05) in rotationally stocked paddocks compared to NG paddocks in May and October of 2012 and 2013, however reductions (P\u3c 0.05) in water infiltration rates occurred in rotationally stocked paddocks only in October 2012 and 2013. In BL1, visual obstruction was less (P\u3c 0.05) in M paddocks than S and NG paddocks to 15.7 inches high in October 2011. However in BL2, no differences in visual obstruction occurred in October 2012. A single mob- or strip-grazing event of a grassland in the spring may improve the nutritional value of the forage for grazing livestock and habitat for wildlife. However, the extent and longevity of these responses are related to soil moisture at the time of grazing and subsequent management and climatic conditions

Enhancing botanical composition, wildlife habitat and carbon sequestration of pastures in south central Iowa through soil disturbance by mob grazing of beef cattle

As Iowa pastures continue to be dominated by cool-season grass species, strategic integration of a single mob-grazing event into pasture management offers a tool to simultaneously increase productivity of pastures and to improve grassland wildlife habitat through increased biodiversity. However, the success of the maneuver depends on climate, soil and landscape

Drosophila non-muscle myosin II motor activity determines the rate of tissue folding

Non-muscle cell contractility is critical for tissues to adopt shape changes. Although, the non-muscle myosin II holoenzyme (myosin) is a molecular motor that powers contraction of actin cytoskeleton networks, recent studies have questioned the importance of myosin motor activity cell and tissue shape changes. Here, combining the biochemical analysis of enzymatic and motile properties for purified myosin mutants with in vivo measurements of apical constriction for the same mutants, we show that in vivo constriction rate scales with myosin motor activity. We show that so-called phosphomimetic mutants of the Drosophila regulatory light chain (RLC) do not mimic the phosphorylated RLC state in vitro. The defect in the myosin motor activity in these mutants is evident in developing Drosophila embryos where tissue recoil following laser ablation is decreased compared to wild-type tissue. Overall, our data highlights that myosin activity is required for rapid cell contraction and tissue folding in developing Drosophila embryos

Finishing Beef Cattle on Grass Supplemented with Self-fed By-Products

Consumers are showing increasing interest in beef from cattle that are finished or fattened on grass rather than in a conventional feedlot. Also recently, Iowa has had a proliferation of plants that produce ethanol from corn. The by-product of this process is distillers dried grains with solubles (DDGS). The objective of this study was to feed beef cattle to market weight (or as near as possible) by grazing them on cool-season grass supplemented with self-fed byproduct pellets

Light-Triggered Myosin Activation for Probing Dynamic Cellular Processes

Shining light on myosin: The incorporation of a caging group onto the essential phosphoserine residue of myosin by protein semisynthesis enables light-triggered activation of the protein (see picture). Caging eliminates the myosin activity, but exposure to 365 nm light restores its function to native levels. The caged protein can also be introduced into cells to facilitate studies of myosin with precise spatial and temporal resolution.American Heart Association (Fellowship)National Institutes of Health (U.S.) (NIH Cell Migration Consortium (GM064346))National Institute of General Medical Sciences (U.S.) (Biotechnology Training Grant

Myosin VI and its binding partner optineurin are involved in secretory vesicle fusion at the plasma membrane.

During constitutive secretion, proteins synthesized at the endoplasmic reticulum (ER) are transported to the Golgi complex for processing and then to the plasma membrane for incorporation or extracellular release. This study uses a unique live-cell constitutive secretion assay to establish roles for the molecular motor myosin VI and its binding partner optineurin in discrete stages of secretion. Small interfering RNA-based knockdown of myosin VI causes an ER-to-Golgi transport delay, suggesting an unexpected function for myosin VI in the early secretory pathway. Depletion of myosin VI or optineurin does not affect the number of vesicles leaving the trans-Golgi network (TGN), indicating that these proteins do not function in TGN vesicle formation. However, myosin VI and optineurin colocalize with secretory vesicles at the plasma membrane. Furthermore, live-cell total internal reflection fluorescence microscopy demonstrates that myosin VI or optineurin depletion reduces the total number of vesicle fusion events at the plasma membrane and increases both the proportion of incomplete fusion events and the number of docked vesicles in this region. These results suggest a novel role for myosin VI and optineurin in regulation of fusion pores formed between secretory vesicles and the plasma membrane during the final stages of secretion