Oscillatory network markers of subcallosal cingulate deep brain stimulation for depression.

Identifying functional biomarkers related to treatment success can aid in expediting therapy optimization, as well as contribute to a better understanding of the neural mechanisms of the treatment-resistant depression (TRD) and subcallosal cingulate deep brain stimulation (SCC-DBS). Magnetoencephalography data were obtained from 16 individuals with SCC-DBS for TRD and 25 healthy subjects. The first objective of the study was to identify region-specific oscillatory modulations that both (i) discriminate individuals with TRD (with SCC-DBS OFF) from healthy controls, and (ii) discriminate TRD treatment responders from non-responders (with SCC-DBS ON). The second objective of this work was to further explore the effects of stimulation intensity and frequency on oscillatory activity in the identified brain regions of interest. Oscillatory power analyses led to the identification of brain regions that differentiated responders from non-responders based on modulations of increased alpha (8-12 Hz) and decreased gamma (32-116 Hz) power within nodes of the default mode, central executive, and somatomotor networks, Broca's area, and lingual gyrus. Within these nodes, it was also found that low stimulation frequency had stronger effects on oscillatory modulation than increased stimulation intensity. The identified functional network biomarkers implicate modulation of TRD-related activity in brain regions involved in emotional control/processing, motor control, and the interaction between speech, vision, and memory, which have all been implicated in depression. These electrophysiological biomarkers have the potential to be used as functional proxies for therapy optimization. Additional stimulation parameter analyses revealed that oscillatory modulations can be strengthened by increasing stimulation intensity or reducing frequency, which may represent potential avenues of direction in non-responders.

Associations between patient factors and successful colon capsule endoscopy - A prospective cohort study.

AIM: To establish patient factors associated with a successful colon capsule endoscopy (CCE) test. METHOD: This prospective cohort study used data collected from patients who underwent CCE as part of the ScotCap evaluation prior to April 2020. A CCE was defined as successful if the capsule visualized the whole colon and rectum (complete test) with sufficient bowel cleansing to permit assessment of the colonic mucosa (adequate bowel preparation). Factors from patients in symptomatic and surveillance groups were analysed for associations with a successful test, complete test, adequate bowel preparation and requirement for further procedure using univariate, multivariate logistic, least absolute shrinkage and selection operator regression. RESULTS: Data from 263 symptomatic and 137 surveillance patients were analysed. There was an association between a symptomatic patient's age and a successful test (OR = 0.97, 95% CI: 0.95-0.99), adequate bowel preparation (OR = 0.97, 95% CI: 0.94-1.00) and further procedure requirement (OR = 1.04, 95% CI: 1.02-1.06). An association was found, for symptomatic patients, between a faecal immunochemical test result in the range 10-399 µg/g and a further procedure (OR = 2.32, 95% CI: 1.23-4.48). In patients undergoing surveillance for previous colorectal cancer (OR = 0.42, 95% CI: 0.18-0.97), had previous bowel resection surgery (OR = 0.43, 95% CI: 0.19-0.98) or took a beta blocker medication (OR = 0.32, 95% CI: 0.11-0.88), an association was found with further procedure requirement. CONCLUSIONS: Among symptomatic patients, younger age was associated with obtaining a successful CCE test. Clinicians could consider patient selection based on these results to improve the rate of successful testing in clinical practice.

An evaluation of a novel bowel preparation regimen and its effect on the utility of colon capsule endoscopy: a prospective cohort study with historical controls.

BACKGROUND: The aim of this study was to evaluate the efficacy of a novel bowel preparation and booster regimen for colon capsule endoscopy (CCE) using macrogol, phospho-soda and gastrografin, compared with a control regimen consisting of polyethylene glycol and sodium picosulfate. METHODS: This was a prospective cohort study using historical controls. Symptomatic patients undergoing CCE between 11/07/2021 and 21/12/2021 using the novel regimen were included. Symptomatic patients who underwent CCE in the ScotCap evaluation using the control regimen were used as historical controls. We measured the rate of complete test (visualisation of the whole colon and rectum), adequate bowel preparation, successful test (complete and adequate bowel preparation) and need for further test following CCE. The rate of adverse events was also collected. RESULTS: Patients undergoing CCE using the new and control regimen were 200 and 316, respectively. The median age, age range and proportion of female patients in the new and control regimen cohorts was 61 vs 60 years, 16-86 vs 20-83 years, and 60.5% vs 56.6%. The rate of complete test, adequate bowel reparation and successful test for the new and control regimen was 69% vs 72.2%, 86.6% vs 80.7% and 60.5% vs 65.8%. Comparing the new and control regimen, 39.5% vs 37.3% of patients required no test following CCE, 26% vs 32.6% required a colonoscopy, 31.5% vs 21.5% required a flexible sigmoidoscopy and 3% vs 2.9% required a computed tomography colonogram. No adverse events were reported using the new regimen compared to 2 (0.6%) in the control group. CONCLUSIONS: The rate of adequate bowel preparation has improved following the introduction of a new regimen. However, further work is needed to increase the complete test rate. A significant proportion of patients continue to avoid colonoscopy following CCE.

A colorectal cancer missed by colon capsule endoscopy: a case report.

BACKGROUND: Colon capsule endoscopy (CCE) is a non-invasive alternative to colonoscopy. The reported sensitivity and specificity of CCE for the detection of clinically significant colonic neoplasia is high. To date, there have been no reported cases of colorectal cancer (CRC) missed by CCE which were located in segments adequately visualised by the capsule. CASE PRESENTATION: We present the case of a 71-year-old female, who underwent CCE for new lower gastrointestinal symptoms. The CCE reported 17 polyps (largest size 10 mm) and angiodysplasia. A 40 mm caecal pole tumour, not detected by the CCE, was identified at follow up colonoscopy. Surgical resection was performed, and the pathology sample was reported as moderately differentiated adenocarcinoma, pT2 pN0 (0/19) M0, with no evidence of EMVI. The patient made an uneventful recovery. The caecal pole tumour was not definitively identified on retrospective review of the CCE images. CONCLUSION: To date, this is the first published case of a CRC missed entirely by CCE. Further research is required to allow calculation of the post CCE interval CRC rate to allow comparison with colonoscopy and CT colonogram.

Food for all: designing sustainable and secure future seafood systems.

Food from the sea can make a larger contribution to healthy and sustainable diets, and to addressing hunger and malnutrition, through improvements in production, distribution and equitable access to wild harvest and mariculture resources and products. The supply and consumption of seafood is influenced by a range of 'drivers' including ecosystem change and ocean regulation, the influence of corporations and evolving consumer demand, as well as the growing focus on the importance of seafood for meeting nutritional needs. These drivers need to be examined in a holistic way to develop an informed understanding of the needs, potential impacts and solutions that align seafood production and consumption with relevant 2030 Sustainable Development Goals (SDGs). This paper uses an evidence-based narrative approach to examine how the anticipated global trends for seafood might be experienced by people in different social, geographical and economic situations over the next ten years. Key drivers influencing seafood within the global food system are identified and used to construct a future scenario based on our current trajectory (Business-as-usual 2030). Descriptive pathways and actions are then presented for a more sustainable future scenario that strives towards achieving the SDGs as far as technically possible (More sustainable 2030). Prioritising actions that not only sustainably produce more seafood, but consider aspects of access and utilisation, particularly for people affected by food insecurity and malnutrition, is an essential part of designing sustainable and secure future seafood systems. Supplementary Information: The online version contains supplementary material available at 10.1007/s11160-021-09663-x.

Rapid Whole Genome Sequencing of Serotype K1 Hypervirulent Klebsiella pneumoniae from an Undocumented Chinese Migrant.

BACKGROUND: Hypervirulent Klebsiella pneumoniae causes severe disseminated infections, typically with hepatic and central nervous system involvement including endophthalmitis. Case Presentation. We report a fatal case of an undocumented Chinese migrant in her 60s who presented to the emergency department with abdominal pain, lethargy, and headache over the preceding two weeks. She had a new diagnosis of diabetes mellitus on admission. Computed tomography scan of the thorax, abdomen, and pelvis showed bilateral pneumonia with liver abscesses. The patient was treated with empirical broad-spectrum antibiotics before K. pneumoniae was isolated from cerebrospinal fluid and blood cultures. The isolate was further characterised as a ST23 (ST: sequence type), serotype K1 hypervirulent strain using Nanopore sequencing. Despite admission to the intensive care unit, the patient died within 48 hrs of admission. CONCLUSIONS: This case demonstrates the need for increased awareness of hypervirulent K. pneumoniae, even in countries where it occurs infrequently. Novel, rapid, sequencing technologies can support diagnosis in unusual presentations.

Colon capsule endoscopy: an innovative method for detecting colorectal pathology during the COVID-19 pandemic?

AIM: The coronavirus pandemic has led to significant challenges for healthcare delivery across the globe. Non-emergency endoscopic activity in the UK has been postponed, raising concerns of increased delays in the diagnosis of colorectal cancer and a surge in demand once services resume. Measures to mitigate this risk must be considered. METHOD: This paper reviews various investigative modalities for colorectal disease which could be deployed during cessation of colonoscopy services. We focus on colon capsule endoscopy (CCE) due to its relevance during the COVID-19 pandemic and its ability to triage patients effectively to further endoscopic investigations. RESULTS: CT of the abdomen and pelvis has been suggested as a triage tool while access to colonoscopy is limited. However, CT may lead to the spread of COVID-19 as patients attend the hospital, and it exposes them to the risks of radiation. Faecal immunochemistry tests have been demonstrated as a good predictor of colonic pathology and could be safely used to risk stratify patients when prioritizing colonoscopy. CCE is a safe and innovative technology for investigating the colon. Procedures can be carried out in the community and can be conducted safely during the coronavirus pandemic. It has been shown to be an accurate detector of colonic neoplasia and can reduce demand for colonoscopy. CONCLUSION: As colonoscopy services resume, they will probably experience high demand leading to further delays for patients. CCE could be used to reduce the number of patients requiring colonoscopy and triage those requiring further endoscopic investigations appropriately.

Colon capsule endoscopy.

There are multiple indications for luminal imaging of the colon. From assessment of known disease, to diagnosing new pathology; intra-luminal visualisation is the mainstay of gastrointestinal diagnosis. Colonoscopy and radiological imaging are currently the most frequently deployed diagnostic methods. However, both have an associated risk profile, have significant resource pressures and are not universally tolerated. Colon capsule endoscopy (CCE) offers an adjunct to these diagnostic options. In this narrative review the utility of CCE is described. Its current uses, potential benefits and future developments are also discussed.

Antibody-mediated protection against MERS-CoV in the murine model.

Murine antisera with neutralising activity for the coronavirus causative of Middle East respiratory syndrome (MERS) were induced by immunisation of Balb/c mice with the receptor binding domain (RBD) of the viral Spike protein. The murine antisera induced were fully-neutralising in vitro for two separate clinical strains of the MERS coronavirus (MERS-CoV). To test the neutralising capacity of these antisera in vivo, susceptibility to MERS-CoV was induced in naive recipient Balb/c mice by the administration of an adenovirus vector expressing the human DPP4 receptor (Ad5-hDPP4) for MERS-CoV, prior to the passive transfer of the RBD-specific murine antisera to the transduced mice. Subsequent challenge of the recipient transduced mice by the intra-nasal route with a clinical isolate of the MERS-CoV resulted in a significantly reduced viral load in their lungs, compared with transduced mice receiving a negative control antibody. The murine antisera used were derived from mice which had been primed sub-cutaneously with a recombinant fusion of RBD with a human IgG Fc tag (RBD-Fc), adsorbed to calcium phosphate microcrystals and then boosted by the oral route with the same fusion protein in reverse micelles. The data gained indicate that this dual-route vaccination with novel formulations of the RBD-Fc, induced systemic and mucosal anti-viral immunity with demonstrated in vitro and in vivo neutralisation capacity for clinical strains of MERS-CoV.

Stable-isotope analysis: a neglected tool for placing parasites in food webs.

Parasites are often overlooked in the construction of food webs, despite their ubiquitous presence in almost every type of ecosystem. Researchers who do recognize their importance often struggle to include parasites using classical food-web theory, mainly due to the parasites' multiple hosts and life stages. A novel approach using compound-specific stable-isotope analysis promises to provide considerable insight into the energetic exchanges of parasite and host, which may solve some of the issues inherent in incorporating parasites using a classical approach. Understanding the role of parasites within food webs, and tracing the associated biomass transfers, are crucial to constructing new models that will expand our knowledge of food webs. This mini-review focuses on stable-isotope studies published in the past decade, and introduces compound-specific stable-isotope analysis as a powerful, but underutilized, newly developed tool that may answer many unresolved questions regarding the role of parasites in food webs.

Building blue infrastructure: Assessing the key environmental issues and priority areas for ecological engineering initiatives in Australia's metropolitan embayments.

Ecological engineering principles are increasingly being applied to develop multifunctional artificial structures or rehabilitated habitats in coastal areas. Ecological engineering initiatives are primarily driven by marine scientists and coastal managers, but often the views of key user groups, which can strongly influence the success of projects, are not considered. We used an online survey and participatory mapping exercise to investigate differences in priority goals, sites and attitudes towards ecological engineering between marine scientists and coastal managers as compared to other stakeholders. The surveys were conducted across three Australian cities that varied in their level of urbanisation and environmental pressures. We tested the hypotheses that, relative to other stakeholders, marine scientists and coastal managers will: 1) be more supportive of ecological engineering; 2) be more likely to agree that enhancement of biodiversity and remediation of pollution are key priorities for ecological engineering; and 3) identify different priority areas and infrastructure or degraded habitats for ecological engineering. We also tested the hypothesis that 4) perceptions of ecological engineering would vary among locations, due to environmental and socio-economic differences. In all three harbours, marine scientists and coastal managers were more supportive of ecological engineering than other users. There was also greater support for ecological engineering in Sydney and Melbourne than Hobart. Most people identified transport infrastructure, in busy transport hubs (i.e. Circular Quay in Sydney, the Port in Melbourne and the Waterfront in Hobart) as priorities for ecological engineering, irrespective of their stakeholder group or location. There were, however, significant differences among locations in what people perceive as the key priorities for ecological engineering (i.e. biodiversity in Sydney and Melbourne vs. pollution in Hobart). Greater consideration of these location-specific differences is essential for effective management of artificial structures and rehabilitated habitats in urban embayments.

Intensity-modulated Radiotherapy for Anal Cancer: Dose-Volume Relationship of Acute Gastrointestinal Toxicity and Disease Outcomes.

AIMS: Intensity-modulated radiotherapy (IMRT) is increasingly used in the treatment delivery of chemoradiotherapy in anal cancer with the ability to reduce toxicity. We report on 4 year outcomes since the introduction of IMRT and identify the most predictive bowel organ at risk that correlates with acute diarrhoea. MATERIALS AND METHODS: Fifty-eight patients receiving definitive chemoradiotherapy for squamous or basaloid cell anal carcinoma (T1-4NanyM0) were reviewed. Fifty-four per cent of patients had stage III disease and most (79%) were treated with a dose of 54 Gy in 30 fractions. Patient acute gastrointestinal toxicity was recorded using Common Terminology Criteria of Adverse Events (CTCAE) diarrhoea grading. Four different methods of bowel were re-contoured for each patient and correlated with acute diarrhoea. Locoregional control and overall survival were analysed. RESULTS: CTCAE grade 3 or more diarrhoea occurred in 11/58 patients (19%). Seven patients did not complete treatment; 10 patients (17%) required a treatment break of 3 or more days. 'Bowel cavity' was the best predictor of acute grade 3 toxicity using volume (P = 0.002) or volume to bowel cavity in 5 Gy bins (V5-V50Gy); P < 0.05. Bowel cavity V30Gy ≤ 300 cm3 predicts a 6% grade 3 diarrhoea risk versus > 300 cm3 predicts a 42% risk. Four year progression-free survival was 84% (95% confidence interval 73-92%) and overall survival was 88% (95% confidence interval 75-95%). CONCLUSION: Chemoradiation using IMRT provides excellent local control and acceptable acute gastrointestinal toxicity. Bowel cavity is the most sensitive predictor for grade 3 versus grade 0-2 diarrhoea, with any volume receiving 5-50 Gy discriminatory.

Dual route vaccination for plague with emergency use applications.

Here, we report a dual-route vaccination approach for plague, able to induce a rapid response involving systemic and mucosal immunity, whilst also providing ease of use in those resource-poor settings most vulnerable to disease outbreaks. This novel vaccine (VypVaxDuo) comprises the recombinant F1 and V proteins in free association. VypVaxDuo has been designed for administration via a sub-cutaneous priming dose followed by a single oral booster dose and has been demonstrated to induce early onset immunity 14 days after the primary immunisation; full protective efficacy against live organism challenge was achieved in Balb/c mice exposed to 2 × 104 median lethal doses of Yersinia pestis Co92, by the sub-cutaneous route at 25 days after the oral booster immunisation. This dual-route vaccination effectively induced serum IgG and serum and faecal IgA, specific for F1 and V, which constitute two key virulence factors in Y. pestis, and is therefore suitable for further development to prevent bubonic plague and for evaluation in models of pneumonic plague. This is an essential requirement for control of disease outbreaks in areas of the world endemic for plague and is supported further by the observed exceptional stability of the primary vaccine formulation in vialled form under thermostressed conditions (40 °C for 29 weeks, and 40 °C with 75% relative humidity for 6 weeks), meaning no cold chain for storage or distribution is needed. In clinical use, the injected priming dose would be administered on simple rehydration of the dry powder by means of a dual barrel syringe, with the subsequent single booster dose being provided in an enteric-coated capsule suitable for oral self-administration.

Metal and Isotope Analysis of Bird Feathers in a Contaminated Estuary Reveals Bioaccumulation, Biomagnification, and Potential Toxic Effects.

The Derwent estuary, in south east Tasmania, is highly contaminated with heavy metals, mainly due to past industrial pollution. This study sought to determine the extent of contamination, bioaccumulation, and biomagnification in the resident bird community and therefore to infer the potential for adverse effects in birds. Thirteen metals were measured from breast feathers (n = 51 individuals) of eight sympatric species of aquatic bird. Stable carbon (δ13C) and nitrogen (δ15N) isotopes were used to identify dietary sources of contaminants, trophic level, and potential biomagnification through food chains. Generalised linear models revealed that metal burdens were often poorly correlated with δ 13C, indicating their uptake from a range of freshwater, brackish, and marine carbon sources-not surprising due to widespread contamination across the tidal estuary. Feather mercury increased significantly with trophic level (inferred from δ15N). White-bellied Sea-eagle Haliaeetus leucogaster samples contained 240 times more mercury than feral Goose Anser cygnoides. Feather arsenic and copper concentrations were significantly higher in birds feeding lower in the food chain. For several piscivorous species, both chick and adults were sampled revealing significantly higher feather mercury, zinc, and selenium in adults. Feathers from birds found dead along the banks of the estuary had significantly higher lead loads than from live birds, and numerous individuals had levels of mercury, zinc, and lead above toxic thresholds reported in other studies. These results highlight the need to include biota from higher trophic levels in contaminant monitoring programs to understand fully the fate and broader implications of contaminants in the environment.

Macrophytes as bioindicators of heavy metal pollution in estuarine and coastal environments.

The Derwent estuary, in Tasmania (Australia), is highly contaminated with heavy metals with significant levels in both sediments and benthic fauna. However, little is known about metal content in benthic primary producers. We characterized metal content (Arsenic, Cadmium, Copper, Lead, Selenium and Zinc) in twelve species of macrophyte, including red, green, and brown algae, and seagrasses, from the Derwent. The metals, arsenic, copper, lead, and Zinc were detected in all of the macrophytes assessed, but the levels differed between species. Seagrasses accumulated the highest concentrations of all metals; with Zn levels being particularly high in the seagrass Ruppia megacarpa (from the upper Estuary) and Pb was detected in Zostera muelleri (from the middle estuary). Ulva australis was ubiquitous throughout the middle-lower estuary and accumulated Zn in relatively high concentrations. The findings suggest that analysis of multiple species may be necessary for a comprehensive understanding of estuary-wide metal pollution.

Determining the Effect of Drying Time on Phosphorus Solubilization from Three Agricultural Soils under Climate Change Scenarios.

Climate projections for the future indicate that the United Kingdom will experience hotter, drier summers and warmer, wetter winters, bringing longer dry periods followed by rewetting. This will result in changes in phosphorus (P) mobilization patterns that will influence the transfer of P from land to water. We tested the hypothesis that changes in the future patterns of drying-rewetting will affect the amount of soluble reactive phosphorus (SRP) solubilized from soil. Estimations of dry period characteristics (duration and temperature) under current and predicted climate were determined using data from the UK Climate Projections (UKCP09) Weather Generator tool. Three soils (sieved <2 mm), collected from two regions of the United Kingdom with different soils and farm systems, were dried at 25°C for periods of 0, 2, 4, 5, 6, 8, 10, 15, 20, 25, 30, 60, and 90 d, then subsequently rewetted (50 mL over 2 h). The solubilized leachate was collected and analyzed for SRP. In the 2050s, warm period temperature extremes >25°C are predicted in some places and dry periods of 30 to 90 d extremes are predicted. Combining the frequency of projected dry periods with the SRP concentration in leachate suggests that this may result overall in increased mobilization of P; however, critical breakpoints of 6.9 to 14.5 d dry occur wherein up to 28% more SRP can be solubilized following a rapid rewetting event. The precise cause of this increase could not be identified and warrants further investigation as the process is not currently included in P transfer models.

Photosynthetic and ultrastructural responses of Ulva australis to Zn stress.

This research evaluated the effect of zinc (Zn) on the ultrastructure and the photosynthetic efficiency of a common green alga. Ulva australis was grown in the laboratory for 7days under a range of different Zn concentrations (0, 25, 50 and 100µgL-1). Growth rate (Gr), photosynthetic efficiency (Fv/Fm and ETRmax), photosynthetic pigments, and metal accumulation were measured. Samples of 1mm length were taken to analyse the effect of Zn on the ultrastructure using transmission electron microscopy (TEM) and cytochemical responses (TB-O and PAS) were evaluated by light microscopy (LM). There were no significant differences in the growth rate, Fv/Fm, ETRmax and the photosynthetic pigments chlorophyll a, chlorophyll b and carotenoids (p>0.05) after 7days of Zn exposure. However, TEM revealed cytoplasm retraction, compression of cellulose fibrils, dissembled thylakoids and electron-dense bodies suggesting ultrastructural impacts from metal exposure and accumulation. Cytological analysis demonstrated that Zn affected U. australis cells at the three concentrations tested. The main effect was cytoplasm retraction and a decrease on the amount of starch granules, following exposure at 25µgL-1 and 50µgL-1 of Zn. We conclude that concentrations of Zn assessed in U. australis in this research has a short-term cellular effect as revealed by TEM and cytological analysis, demonstrating the importance of measuring a broad suite of endpoints to better understand species responses to environmentally relevant concentrations of Zn. However, U. australis was able to physiologically tolerate adverse conditions, since there was no effect on the photosynthetic performance and growth.

Major agricultural changes required to mitigate phosphorus losses under climate change.

Phosphorus losses from land to water will be impacted by climate change and land management for food production, with detrimental impacts on aquatic ecosystems. Here we use a unique combination of methods to evaluate the impact of projected climate change on future phosphorus transfers, and to assess what scale of agricultural change would be needed to mitigate these transfers. We combine novel high-frequency phosphorus flux data from three representative catchments across the UK, a new high-spatial resolution climate model, uncertainty estimates from an ensemble of future climate simulations, two phosphorus transfer models of contrasting complexity and a simplified representation of the potential intensification of agriculture based on expert elicitation from land managers. We show that the effect of climate change on average winter phosphorus loads (predicted increase up to 30% by 2050s) will be limited only by large-scale agricultural changes (e.g., 20-80% reduction in phosphorus inputs).The impact of climate change on phosphorus (P) loss from land to water is unclear. Here, the authors use P flux data, climate simulations and P transfer models to show that only large scale agricultural change will limit the effect of climate change on average winter P loads in three catchments across the UK.

Fine-tuning transmission electron microscopy methods to evaluate the cellular architecture of Ulvacean seaweeds (Chlorophyta).

Chemical fixation is a critical step in the analysis of the ultrastructure of seaweeds because the wrong approach can compromise the ability to distinguish fine-scale cellular composition. Fixation agents, fixation time and type of tissue are important factors to consider for transmission electron microscopy (TEM), and not every protocol is suitable for all cell types. We evaluated a range of fixation agents, post-fixation time and dehydration solutions to determine a TEM protocol for seaweeds in the Family Ulvaceae. We assessed Ulva lactuca using 5 protocols. The level of preservation obtained differed markedly between fixation methods The best result was obtained by fixing the sample with 2.5% glutaraldehyde, 0.05M sodium cacodylate buffer and 2% paraformaldehyde overnight, and 8h post-fixation in 1% in osmium tetroxide 1%. This approach and fixation time ensured that the membranes, especially the thylakoid membranes of chloroplasts, remained intact. Ethanol is recommended for dehydration as the use of acetone for dehydration resulted in the collapse of cellular membranes. This new protocol will ensure the ultrastructure of Ulvacean seaweeds can be clearly ascertained in the future.

Spatial variation in soil properties and diffuse losses between and within grassland fields with similar short-term management.

One of the major challenges for agriculture is to understand the effects of agricultural practices on soil properties and diffuse pollution, to support practical farm-scale land management. Three conventionally managed grassland fields with similar short-term management, but different ploughing histories, were studied on a long-term research platform: the North Wyke Farm Platform. The aims were to (i) quantify the between-field and within-field spatial variation in soil properties by geostatistical analysis, (ii) understand the effects of soil condition (in terms of nitrogen, phosphorus and carbon contents) on the quality of discharge water and (iii) establish robust baseline data before the implementation of various grassland management scenarios. Although the fields sampled had experienced the same land use and similar management for at least 6 years, there were differences in their mean soil properties. They showed different patterns of soil spatial variation and different rates of diffuse nutrient losses to water. The oldest permanent pasture field had the largest soil macronutrient concentrations and the greatest diffuse nutrient losses. We show that management histories affect soil properties and diffuse losses. Potential gains in herbage yield or benefits in water quality might be achieved by characterizing every field or by area-specific management within fields (a form of precision agriculture for grasslands). Permanent pasture per se cannot be considered a mitigation measure for diffuse pollution. The between- and within-field soil spatial variation emphasizes the importance of baseline characterization and will enable the reliable identification of any effects of future management change on the Farm Platform. HIGHLIGHTS: Quantification of soil and water quality in grassland fields with contrasting management histories.Considerable spatial variation in soil properties and diffuse losses between and within fields.Contrasting management histories within and between fields strongly affected soil and water quality.Careful pasture management needed: the oldest pasture transferred the most nutrients from soil to water.