Economic impact of Wheat streak mosaic virus in the Texas High Plains

Wheat streak mosaic virus, vectored by the wheat curl mite Aceria tosichella Keifer, is a major limiting factor in wheat production in the Texas Panhandle. It is the most frequently encountered virus in the region, affecting both shoot and root biomass, and consequently it can drastically reduce both forage and grain yield, and water-use efficiency of the plant. In light of the continuing decline of water levels in the Ogallala Aquifer, its effect on water-use efficiency has significant implications for irrigated fields, especially with regard to energy costs for pumping water. This article estimates the potential economic losses from the virus infection. To achieve this objective, partial budgeting techniques, based primarily on data from field experiments, were used. Results indicate that Wheat streak mosaic virus causes grain and forage yield losses that significantly affect profits from wheat production. In addition, irrigated wheat producers are more negatively affected by the disease due to the economic losses from reduced water-use efficiency of infected plants. The economic insights from this article provide important implications for wheat management and research priority-setting.     

Productivity of temperate broad-leaved forest stands differing in tree species diversity

? Understanding the effects of tree species diversity on biomass and production of forests is fundamental for carbon sequestration strategies, particularly in the perspective of the current climate change. However, the diversity-productivity relationship in old-growth forests is not well understood.

? We quantified biomass and above-ground production in nine forest stands with increasing tree species diversity from monocultures of beech to stands consisting of up to five deciduous tree species (Fagus sylvatica, Fraxinus excelsior, Tilia spp., Carpinus betulus, Acer spp.) to examine (a) if mixed stands are more productive than monospecific stands, (b) how tree species differ in the productivity of stem wood, leaves and fruits, and (c) if beech productivity increases with tree diversity due to lower intraspecific competition and complementary resource use.

? Total above-ground biomass and wood production decreased with increasing tree species diversity. In Fagus and Fraxinus, the basal area-related wood productivity exceeded those of the co-occurring tree species, while Tilia had the highest leaf productivity. Fagus trees showed no elevated production per basal area in the mixed stands.

? We found no evidence of complementary resource use associated with biomass production. We conclude that above-ground productivity of old-growth temperate deciduous forests depend more on tree species-specific traits than on tree diversity itself.

     

Diversity of human copy number variation and multicopy genes

Copy number variants affect both disease and normal phenotypic variation, but those lying within heavily duplicated, highly identical sequence have been difficult to assay. By analyzing short-read mapping depth for 159 human genomes, we demonstrated accurate estimation of absolute copy number for duplications as small as 1.9 kilobase pairs, ranging from 0 to 48 copies. We identified 4.1 million "singly unique nucleotide" positions informative in distinguishing specific copies and used them to genotype the copy and content of specific paralogs within highly duplicated gene families. These data identify human-specific expansions in genes associated with brain development, reveal extensive population genetic diversity, and detect signatures consistent with gene conversion in the human species. Our approach makes ~1000 genes accessible to genetic studies of disease association.     

Exclusion of Vibrio spp. by an antagonistic marine actinomycete Streptomyces rubrolavendulae M56

A marine actinomycete Streptomyces rubrolavendulae M56 isolated from the sediments of Bay of Bengal and displaying biogranulation property was used for the study. The strain showed antagonistic property against vibrios, the opportunistic pathogens in aquaculture. The efficacy of the biogranules of actinomycete M56 in competitive exclusion of Vibrio spp. was tested both in vitro and in vivo. Streptomyces rubrolavendulae M56 biogranules could significantly exclude the pathogenic Vibrio spp. in co‐culture experiments (in vitro). In vivo exclusion of Vibrio spp. in a Penaeus monodon postlarval rearing system was evaluated by treatment of the rearing water with biogranules of S. rubrolavendulae M56. The experiments proved that S. rubrolavendulae M56 biogranules could reduce the pathogenic Vibrio spp., while maintaining total heterotrophic bacterial count. Therefore, the actinomycete biogranules (M56) can be used as a promising alternative to antibiotics in the shrimp larval production system which is often affected by vibriosis.     

Effect of feeding intensity and milking system on nutritionally relevant milk components in dairy farming systems in the North East of England

There is increasing concern that the intensification of dairy production reduces the concentrations of nutritionally desirable compounds in milk. This study therefore compared important quality parameters (protein and fatty acid profiles; α-tocopherol and carotenoid concentrations) in milk from four dairy systems with contrasting production intensities (in terms of feeding regimens and milking systems). The concentrations of several nutritionally desirable compounds (β-lactoglobulin, omega-3 fatty acids, omega-3/omega-6 ratio, conjugated linoleic acid c9t11, and/or carotenoids) decreased with increasing feeding intensity (organic outdoor ≥ conventional outdoor ≥ conventional indoors). Milking system intensification (use of robotic milking parlors) had a more limited effect on milk composition, but increased mastitis incidence. Multivariate analyses indicated that differences in milk quality were mainly linked to contrasting feeding regimens and that milking system and breed choice also contributed to differences in milk composition between production systems.     

Fungal endophyte infection increases carbon sequestration potential of southeastern USA tall fescue stands

Tall fescue (Schedonorus arundinaceous (Schreb.)) is often infected with a common toxic fungal endophyte (Neotyphodium coenophialum) capable of producing alkaloids that affect grazing animal health, insect herbivory, plant production, and litter decomposition. The strength of these endophyte-associated effects is thought to depend on the abiotic and biotic conditions of a specific site. Prior work from Georgia, USA, has demonstrated that fungal endophyte infection can increase soil carbon pools of tall fescue pastures; however, for endophyte infection to contribute substantially to regional carbon sequestration, this result would have to hold true across the broad range of environmental conditions that support tall fescue growth. In this study, we evaluated whether endophyte infection consistently alters various soil parameters, including carbon storage, of tall fescue stands located throughout the southeastern United States. Soil samples were collected from nine sites with established paired high- and low- endophyte-infected tall fescue stands. These samples were analyzed for basic soil parameters, soil organic carbon (SOC), soil total nitrogen (TN), particulate and non-particulate organic matter-C and -N (POM, n-POM), C and N mineralization rates, and microbial biomass and community composition. Averaged across all sites, endophyte-infected tall fescue stands had 6% greater SOC and 5% greater TN pools in surface soil than adjacent endophyte-free stands. The lack of a significant interaction between site and endophyte infection status indicated that this result was relatively consistent across sites, despite differences in stand age, climate, and other environmental conditions. While POM C and POM N tended to be higher in endophyte-infected than endophyte-free stands, this result was not significant. However, greater pools of n-POM C and N were observed in endophyte-infected vs. endophyte-free stands when averaged across all the sites, suggesting increased retention of recalcitrant substrates occurred in response to fungal endophyte infection. Total microbial biomass, measured via phospholipid fatty acid (PLFA) analysis, was greater in endophyte-infected than endophyte-free soils when averaged across sites, reflecting the trends observed with SOC and TN. Microbial community composition shifted somewhat in response to fungal endophyte infection: significantly higher fungal to bacterial ratios were observed in endophyte-free compared to endophyte-infected stands. However, ordinations of the PLFA data demonstrated only slight separation of endophyte-infected and endophyte-free microbial communities at some sites and no clear separation at others. Enhanced SOC, TN, recalcitrant n-POM C and N pools, and altered microbial biomass and communities suggest that this aboveground fungal endophyte symbiosis has widespread effects on soil biology and biochemistry, and that high prevalence of the aboveground endophyte increases C sequestration capacity of tall fescue stands throughout the southeastern USA.     

Validating the assessment of bull sperm morphology by veterinary practitioners

The objective of this study was to validate the assessment of bull sperm morphology done by veterinary practitioners. Out of 1606 bulls, 1400 (87.2%) and 1344 (83.7%) were designated by practitioners and an experienced andrologist, respectively, as having > 70% morphologically normal sperm. In 92% of the evaluations, there was agreement between the designations chosen.     

Modeling soil metabolic processes using isotopologue pairs of position-specific C-labeled glucose and pyruvate

Most organic carbon (C) in soils eventually turns into CO₂ after passing through microbial metabolic pathways, while providing cells with energy and biosynthetic precursors. Therefore, detailed insight into these metabolic processes may help elucidate mechanisms of soil C cycling processes. Here, we describe a modeling approach to quantify the C flux through metabolic pathways by adding 1-¹³C and 2,3-¹³C pyruvate and 1-¹³C and U-¹³C glucose as metabolic tracers to intact soil microbial communities. The model calculates, assuming steady-state conditions and glucose as the only substrate, the reaction rates through glycolysis, Krebs cycle, pentose phosphate pathway, anaplerotic activity through pyruvate carboxylase, and various biosynthesis reactions. The model assumes a known and constant microbial proportional precursor demand, estimated from literature data. The model is parameterized with experimentally determined ratios of ¹³CO₂ production from pyruvate and glucose isotopologue pairs. Model sensitivity analysis shows that metabolic flux patterns are especially responsive to changes in experimentally determined ¹³CO₂ ratios from pyruvate and glucose. Calculated fluxes are far less sensitive to assumptions concerning microbial chemical and community composition. The calculated metabolic flux pattern for a young volcanic soil indicates significant pentose phosphate pathway activity in excess of pentose precursor demand and significant anaplerotic activity. These C flux patterns can be used to calculate C use efficiency, energy production and consumption for growth and maintenance purposes, substrate consumption, nitrogen demand, oxygen consumption, and microbial C isotope composition. The metabolic labeling and modeling methods may improve our ability to study the biochemistry and ecophysiology of intact and undisturbed soil microbial communities.     

Pharmacokinetics of subcutaneously administered doramectin in alpacas

The objective of this research was to evaluate comparative pharmacokinetics of doramectin in alpacas, after subcutaneous administration of 0.2 mg/kg dose. Six healthy adult alpacas, mean age of 5 years ± 1, (three female and three gelded males) of mean bodyweight of 62 kg ± 16 kg with an average body condition scored 2.8 ± 1 out of five, were used in this study. Serial blood samples were collected from the jugular vein before the administration until day 21 afterwards to establish the pharmacokinetics of doramectin after its subcutaneous administration at 0.2 mg/kg dose. The blood samples were analysed using high-performance liquid chromatography (HPLC), fluorescence detection method with precolumn derivatisation, validated for alpacas. The pharmacokinetic parameters were calculated using a noncompartmental model, and results showed Cmax (6.05 ± 5.34 ng/ml), Tmax (3.83 ± 2.48 days), AUC (62.12 ± 18.86 ng/ml × d), terminal half-life (6.2 ± 4.9 days) and MRT (11.56 ± 4.43 days). The results of this study showed that the Cmax and AUC were much lower than in cattle and sheep at the same dosage. Tmax remained similar to cattle and sheep. This study presents valuable information about pharmacokinetics of doramectin in alpacas, which can be utilised in its future efficacy studies.