Quantification of Peyer's patches in Cheviot sheep for future scrapie pathogenesis studies

Peyer's patches (PPs) are the most probable sites of intestinal uptake of the transmissible spongiform encephalopathy (TSE) agent. The amount of PP tissue varies considerably between different age groups of individuals, and whether this variation is related to susceptibility to TSE infection raises an intriguing possibility. The purpose of this study was to determine the surface area of PP tissue and the number of associated lymphoid follicles in different age groups of Neuropathogenesis Unit (NPU) Cheviot sheep. Terminal ilea were obtained from 33 sheep of different ages. Samples of ileal tissue were collected for immunocytochemistry and immunolabelled for prion protein (PrP). Specimens were then fixed in acetic acid, stained with methylene blue and transilluminated. Image analysis software was used to calculate the area of intestinal and PP tissue. The number of associated lymphoid follicles was determined using a dissecting microscope. Results showed a marked fall in surface area of PP tissue and lymphoid follicle density around puberty (about 8-9 months of age in NPU Cheviot sheep) and both measures remained low throughout adulthood. Using the Spearman's rank correlation coefficient, r(s), these two measures were found to be closely correlated (r(s)=0.899, n=33, P<0.0001). There was also a significant (negative) correlation between age and the two respective measures (surface area of PP tissue versus age, r(s)=-0.879 (n=33, P<0.0001); lymphoid follicle density versus age r(s)=-0.943 (n=33, P<0.0001). Immunolabelling for PrP was observed primarily in the light zone of lymphoid follicles. Results obtained from this study are useful for future oral pathogenesis studies of the NPU Cheviot flock. They may also offer a possible biological explanation for the apparent age-susceptibility relationship observed in natural cases of TSEs and might help to explain the young age-distribution of cases.     

Quantifying inherent predictability and spatial synchrony in the aphid vector Myzus persicae: field-scale patterns of abundance and regional forecasting error in the UK

Background

Sugar beet is threatened by virus yellows, a disease complex vectored by aphids that reduces sugar content. We present an analysis of Myzus persicae population dynamics with and without neonicotinoid seed treatment. We use 6 years' yellow water trap and field-collected aphid data and two decades of 12.2 m suction-trap aphid migration data. We investigate both spatial synchrony and forecasting error to understand the structure and spatial scale of field counts and why forecasting aphid migrants lacks accuracy. Our aim is to derive statistical parameters to inform regionwide pest management strategies.

Results

Spatial synchrony, indicating the coincident change in counts across the region over time, is rarely present and is best described as stochastic. Uniquely, early season field populations in 2019 did show spatial synchrony to 90 km compared to the overall average weekly correlation length of 23 km. However, 70% of the time series were spatially heterogenous, indicating patchy between-field dynamics. Field counts lacked the same seasonal trend and did not peak in the same week. Forecasts tended to under-predict mid-season log₁₀ counts. A strongly negative correlation between forecasting error and the proportion of zeros was shown.

Conclusion

Field populations are unpredictable and stochastic, regardless of neonicotinoid seed treatment. This outcome presents a problem for decision-support that cannot usefully provide a single regionwide solution. Weighted permutation entropy inferred that M. persicae 12.2 m suction-trap time series had moderate to low intrinsic predictability. Early warning using a migration model tended to predict counts at lower levels than observed. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Vulnerability of coffee (Coffea spp.) genetic resources in the United States

Genetic Resources and Crop Evolution - Coffee is one of the most important agricultural commodities worldwide, significantly contributing to the economies of many coffee-producing countries....     

Massive CO₂ ice deposits sequestered in the south polar layered deposits of Mars

Shallow Radar soundings from the Mars Reconnaissance Orbiter reveal a buried deposit of carbon dioxide (CO(2)) ice within the south polar layered deposits of Mars with a volume of 9500 to 12,500 cubic kilometers, about 30 times that previously estimated for the south pole residual cap. The deposit occurs within a stratigraphic unit that is uniquely marked by collapse features and other evidence of interior CO(2) volatile release. If released into the atmosphere at times of high obliquity, the CO(2) reservoir would increase the atmospheric mass by up to 80%, leading to more frequent and intense dust storms and to more regions where liquid water could persist without boiling.     

Microsatellite markers as a tool for active germplasm management and bridging the gap between national and local collections of apple

Genetic Resources and Crop Evolution - Simple sequence repeat (SSR) microsatellite markers have been extensively used to identify duplication and analyse genetic diversity in germplasm collections...     

Review of Integrated Nutrient Management for Sustainable Crop Production

This study analyses the influences of sociodemographic factors, business orientation of farmers, and farm characteristics on adoption of ICT-based information through primary data collected from 461 farmers in eight districts of Uttar Pradesh, India. A personal interview survey was conducted using a pre-tested structured questionnaire. The Poisson Count Regression Model was used to analyze the factors influencing use of the information derived through ICT-based systems on various agricultural practices. The findings indicate that education, income, and social category of farmers are important sociodemographic factors affecting the adoption of ICT-based information systems. Similarly, farmers who consider farming as a business venture, practice a diversified cropping system, and have small farms are more likely to use ICT-based information.     

Horticultural Use of Copper-Based Fungicides Has Not Increased Copper Concentrations in Sediments in the Mid- and Upper Yarra Valley

The use of Cu-based fungicide can pose a risk to nearby surface water bodies due to the run-off of accumulated Cu from agricultural soils. In 2008, we conducted a reconnaissance survey of the presence and concentration of copper in sediments at 18 sites within the Yarra River Catchment, an important horticultural production system in south-eastern Australia. Observed Cu concentrations in sediment samples from the study sites (mean (95 % confidence interval) 12.0 (10.6–13.6)? mg/kg dry weight) were similar to the concentrations present in the samples from the reference sites (mean (95 % confidence interval) 12.0 (6.7–16.8)? mg/kg dry weight). The data on Cu and other metals in the sediments suggest that that there is unlikely to have been wide spread, diffuse, off-site transport of Cu from the soils of horticultural properties to nearby surface waterways in the Yarra River Catchment and that that observed sediment metal concentrations are unlikely to pose an ecological risk to sediment-dwelling organisms at the study sites.     

Gene flow from transgenic oilseed Brassica juncea (L.) Czern. into weedy Sinapis arvensis L. (wild mustard)

Gene flow from acetolactate synthase‐resistant (HR) Brassica juncea oilseed canola to related weed, Sinapis arvensis (density 1 plant/m²) was assessed in a 100 m² field plot of HR B. juncea. Two HR F₁ hybrids (H1 and H2) were detected among 109 951 seedlings screened with imazethapyr (hybridization frequency – 1.8 × 10^?5). Hybridity was confirmed using flow cytometry, B. juncea‐specific amplified fragment length polymorphisms (AFLPs) markers, genomic in situ hybridization (GISH) and PCR‐based detection of B. juncea's HR gene. H1 and H2 had 2n = 27 and 2n = 45 chromosomes, corresponding 3x (SrAB) and 5x (SrAABB) genomic structures and reduced male fertility, 3.2 and 16.6% pollen viability, respectively. H1 was self‐incompatible, whereas H2 set seed when selfed (B. juncea trait). Selfed F₂, F₃ and F₄ plants showed HR trait persistence and vigorous growth and high (80–100%) pollen fertility in 22% and 39% of the F₂ and F₃ plants, respectively. No progeny were obtained from F_1, F₂ or F₃ hybrids × S. arvensis backcrosses, suggesting the likelihood of introgression of traits is low to negligible.