Impact of irrigation scheduling practices on pesticide leaching at a regional level

A modelling approach was used to evaluate the scheduling practices of local farmers and two other irrigation scheduling practices for their potential impact on groundwater pollution in Doña Ana County, New Mexico, USA. The irrigation scheduling practices were: tensiometer-based with the tensiometers placed at 50 or 75% of the root-zone depth and irrigations started when tensiometer readings reached 6 kPa for sandy soils, 23 kPa for sandy loam soils, 44 kPa for loamy soils, and 74 kPa for clay loam soils; and at 50% plant available water depletion (PAWD) level regardless of soil type. The objective was to use irrigation scheduling model IRRSCHM, a volume balance, mixing-cell, type irrigation scheduling and pesticide transport model, to assess and compare the impact of different irrigation scheduling practices on cyanazine and metolachlor concentrations at 180 cm below the soil surface during a 30-year cropping sequence. The region was divided into different soil textural classes to facilitate rapid estimation of soil parameters needed for the model. Very low pesticide concentrations were predicted at 180 cm below the soil surface. However, the predicted pesticide concentrations increased as soil sand fractions increased, regardless of the irrigation scheduling practice. The tensiometer based irrigation scheduling resulted in the highest pesticide concentrations. The lowest concentrations were predicted under the farmer's practices due to deficit irrigation. Dual concentrations at 180 cm depth of the sandy soil class were ~20 times less than the Health Advisory Level under the tensiometer-based irrigation scheduling practices, while the farmer's practices resulted in metolachlor concentrations ~625 times less than the Health Advisory Level. Similarly, the predicted cyanazine concentration in sandy soil class was 3125 times less than the Health Advisory Level under the tensiometer-based irrigation scheduling and ~416 000 times less than the Health Advisory Level under farmer's practices. Simulation results suggested that current farmer's practices do not pose a threat to the area's groundwater quality and result in a 15-40% leaching fraction depending on soil type. Tensiometer-based irrigation scheduling was similar to scheduling irrigations at 50% plant available water depletion and resulted in a 35-50% leaching fraction depending on soil type as long as the tensiometer was placed in the proper root zone depth. The model's calculated leaching fractions using farmer's practices were similar to measured leaching fractions in Doña Ana County, giving credibility to the use of simulation models for assessing and comparing the potential impact of different irrigation scheduling practices on environmental quality at a regional level

SAFEGUARDING THE HEALTH OF POTATOES IN SCOTLAND

Summary: An annual programme of testing and surveillance is undertaken by The Scottish Government in order to safeguard potato production in Scotland from quarantine and non-indigenous pests. This includes potato quarantine testing and pathogen testing of nuclear stock, specific surveillance for viroid, bacterial, nematode and insect pests, inspection of seed potatoes and varietal susceptibility testing for potato wart disease (Synchytrium endobioticum) and potato cyst nematodes (Globodera spp.)

The design of organic catalysis for epoxidation by hydrogen peroxide

The potential of various organic species to catalyze epoxidation of ethene by hydrogen peroxide is explored with B3LYP/6-31G* DFT calculations

The structures of a naturally empty cowpea mosaic virus particle and its genome-containing counterpart by cryo-electron microscopy

Cowpea mosaic virus (CPMV) is a picorna-like plant virus. As well as an intrinsic interest in CPMV as a plant pathogen, CPMV is of major interest in biotechnology applications such as nanotechnology. Here, we report high resolution cryo electron microscopy (cryo-EM) maps of wild type CPMV containing RNA-2, and of naturally-formed empty CPMV capsids. The resolution of these structures is sufficient to visualise large amino acids. We have refined an atomic model for each map and identified an essential amino acid involved in genome encapsidation. This work has furthered our knowledge of Picornavirales genome encapsidation and will assist further work in the development of CPMV as a biotechnological tool

Adaptation of a bidirectional crisis and emergency risk communication framework by community-engaged research partnerships in rural Mississippi during the COVID-19 pandemic

Community engagement is important for reaching populations at risk for health inequities in the coronavirus disease 2019 (COVID-19) pandemic. A community-engaged risk communication intervention implemented by a community-engaged research partnership in Southeast Minnesota to address COVID-19 prevention, testing, and socioeconomic impacts has demonstrated high acceptability, feasibility, perceived efficacy, and sustainability. In this study, we describe the adaptation of the intervention by a community-academic partnership with rural African American populations in three Mississippi counties with high COVID-19 disparities. Intervention reach was assessed by the number of messages delivered by Communication Leaders to members of their social networks. Perceived scalability of the intervention was assessed by the Intervention Scalability Assessment Tool. Bidirectional communication between Communication Leaders and community members within their social networks was used by the partnership to refine messages, meet resource needs, and advise statewide decision-makers. In the first 3 months, more than 8482 individuals were reached in the three counties. The intervention was deemed to be highly scalable by partnership members. Adaptation of a community-engaged pandemic CERC intervention is feasible and scalable, and it has the potential to reduce COVID-19 inequities across heterogeneous populations. This approach may be incorporated into current and future pandemic preparedness policies for community engagement

Nanoscale Confinement and Fluorescence Effects of Bacterial Light Harvesting Complex LH2 in Mesoporous Silicas

Many key chemical and biochemical reactions, particularly in living cells, take place in confined space at the mesoscopic scale. Toward understanding of physicochemical nature of biomacromolecules confined in nanoscale space, in this work we have elucidated fluorescence effects of a light harvesting complex LH2 in nanoscale chemical environments. Mesoporous silicas (SBA-15 family) with different shapes and pore sizes were synthesized and used to create nanoscale biomimetic environments for molecular confinement of LH2. A combination of UV-vis absorption, wide-field fluorescence microscopy, and in situ ellipsometry supports that the LH2 complexes are located inside the silica nanopores. Systematic fluorescence effects were observed and depend on degree of space confinement. In particular, the temperature dependence of the steady-state fluorescence spectra was analyzed in detail using condensed matter band shape theories. Systematic electronic-vibrational coupling differences in the LH2 transitions between the free and confined states are found, most likely responsible for the fluorescence effects experimentally observed

CD73 controls Myosin II-driven invasion, metastasis, and immunosuppression in amoeboid pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) has a very poor prognosis because of its high propensity to metastasize and its immunosuppressive microenvironment. Using a panel of pancreatic cancer cell lines, three-dimensional (3D) invasion systems, microarray gene signatures, microfluidic devices, mouse models, and intravital imaging, we demonstrate that ROCK–Myosin II activity in PDAC cells supports a transcriptional program conferring amoeboid invasive and immunosuppressive traits and in vivo metastatic abilities. Moreover, we find that immune checkpoint CD73 is highly expressed in amoeboid PDAC cells and drives their invasive, metastatic, and immunomodulatory traits. Mechanistically, CD73 activates RhoA–ROCK–Myosin II downstream of PI3K. Tissue microarrays of human PDAC biopsies combined with bioinformatic analysis reveal that rounded-amoeboid invasive cells with high CD73–ROCK–Myosin II activity and their immunosuppressive microenvironment confer poor prognosis to patients. We propose targeting amoeboid PDAC cells as a therapeutic strategy.The work was supported by Barts Charity MGU0418 (R.S., O.M., J.M., S.G., and V.S.-M.), Organ-on-a-Chip Network and Emulate Proof of Concept Awards (R.S. and V.S.-M.), Cancer Research UK (CRUK) C33043/A24478 (O.M., L.K., and V.S.-M.), Pancreatic Cancer Research UK Fund (C.M.W.), National Centre for the 3Rs (S.L. and A.B.), The National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London and/or the NIHR Clinical Research Facility (H.L.), and Grant Atracción de Talento Investigador 2019-T1/BMD-13642 funded by Comunidad de Madrid (J.L.O.).Peer reviewe

Landscape history, time lags and drivers of change : urban natural grassland remnants in Potchefstroom, South Africa

The history of the landscape directly affects biotic assemblages, resulting in time lags in species response to disturbances. In highly fragmented environments, this phenomenon often causes extinction debts. However, few studies have been carried out in urban settings. To determine if there are time lags in the response of temperate natural grasslands to urbanization. Does it differ for indigenous species and for species indicative of disturbance and between woody and open grasslands? Do these time lags change over time? What are the potential landscape factors driving these changes? What are the corresponding vegetation changes? In 1995 and 2012 vegetation sampling was carried out in 43 urban grassland sites. We calculated six urbanization and landscape measures in a 500 m buffer area surrounding each site for 1938, 1961, 1970, 1994, 1999, 2006, and 2010. We used generalized linear models and model selection to determine which time period best predicted the contemporary species richness patterns. Woody grasslands showed time lags of 20-40 years. Contemporary open grassland communities were, generally, associated with more contemporary landscapes. Altitude and road network density of natural areas were the most frequent predictors of species richness. The importance of the predictors changed between the different models. Species richness, specifically, indigenous herbaceous species, declined from 1995 to 2012. The history of urbanization affects contemporary urban vegetation assemblages. This indicates potential extinction debts, which have important consequences for biodiversity conservation planning and sustainable future scenarios.Peer reviewe

Tracking down carbon inputs underground from an arid zone Australian calcrete.

Freshwater ecosystems play a key role in shaping the global carbon cycle and maintaining the ecological balance that sustains biodiversity worldwide. Surficial water bodies are often interconnected with groundwater, forming a physical continuum, and their interaction has been reported as a crucial driver for organic matter (OM) inputs in groundwater systems. However, despite the growing concerns related to increasing anthropogenic pressure and effects of global change to groundwater environments, our understanding of the dynamics regulating subterranean carbon flows is still sparse. We traced carbon composition and transformations in an arid zone calcrete aquifer using a novel multidisciplinary approach that combined isotopic analyses of dissolved organic carbon (DOC) and inorganic carbon (DIC) (δ13CDOC, δ13CDIC, 14CDOC and 14CDIC) with fluorescence spectroscopy (Chromophoric Dissolved OM (CDOM) characterisation) and metabarcoding analyses (taxonomic and functional genomics on bacterial 16S rRNA). To compare dynamics linked to potential aquifer recharge processes, water samples were collected from two boreholes under contrasting rainfall: low rainfall ((LR), dry season) and high rainfall ((HR), wet season). Our isotopic results indicate limited changes and dominance of modern terrestrial carbon in the upper part (northeast) of the bore field, but correlation between HR and increased old and 13C-enriched DOC in the lower area (southwest). CDOM results show a shift from terrestrially to microbially derived compounds after rainfall in the same lower field bore, which was also sampled for microbial genetics. Functional genomic results showed increased genes coding for degradative pathways-dominated by those related to aromatic compound metabolisms-during HR. Our results indicate that rainfall leads to different responses in different parts of the bore field, with an increase in old carbon sources and microbial processing in the lower part of the field. We hypothesise that this may be due to increasing salinity, either due to mobilisation of Cl- from the soil, or infiltration from the downstream salt lake during HR. This study is the first to use a multi-technique assessment using stable and radioactive isotopes together with functional genomics to probe the principal organic biogeochemical pathways regulating an arid zone calcrete system. Further investigations involving extensive sampling from diverse groundwater ecosystems will allow better understanding of the microbiological pathways sustaining the ecological functioning of subterranean biota