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Assessment and Validation of Globodera pallida as a Novel In Vivo Model for Studying Alzheimer’s Disease
Get PDFPublication history: Accepted - 11 September 2021; Published online - 19 September 2021.Background: Whole transgenic or non-transgenic organism model systems allow the screening of pharmacological compounds for protective actions in Alzheimer’s disease (AD). Aim: In this study, a plant parasitic nematode, Globodera pallida, which assimilates intact peptides from the external environment, was investigated as a new potential non-transgenic model system of AD. Methods: Fresh second-stage juveniles of G. pallida were used to measure their chemosensory, perform immunocytochemistry on their neurological structures, evaluate their survival rate, measure reactive oxygen species, and determine total oxidized glutathione to reduced glutathione ratio (GSSG/GSH) levels, before and after treatment with 100 µM of various amyloid beta (Aβ) peptides (1–40, 1–42, 17–42, 17–40, 1–28, or 1–16). Wild-type N2 C. elegans (strain N2) was cultured on Nematode Growth Medium and directly used, as control, for chemosensory assays. Results: We demonstrated that: (i) G. pallida (unlike Caenorhabditis elegans) assimilates amyloid-β (Aβ) peptides which co-localise with its neurological structures; (ii) pre-treatment with various Aβ isoforms (1–40, 1–42, 17–42, 17–40, 1–28, or 1–16) impairs G. pallida’s chemotaxis to differing extents; (iii) Aβ peptides reduced survival, increased the production of ROS, and increased GSSG/GSH levels in this model; (iv) this unique model can distinguish differences between different treatment concentrations, durations, and modalities, displaying good sensitivity; (v) clinically approved neuroprotective agents were effective in protecting G. pallida from Aβ (1–42) exposure. Taken together, the data indicate that G. pallida is an interesting in vivo model with strong potential for discovery of novel bioactive compounds with anti-AD activity.N.A.A. received a PhD studentship from Shaqra University, KSA and the Saudi Cultural Bureau in London (UKSACB). B.D.G.’s laboratory has received support for AD research from
Alzheimer’s Research UK (ARUK-NC2019-NI), the Medical Research Council (MRC) (CIC-CD1718-
CIC25), US-Ireland Health and Social Care NI (HSC R&DST/5460/2018) and InvestNI (RD101427
11-01-17-008). This work was also supported by Shaqra University, Saudi Arabi
Lessons to be learned in adoption of autonomous equipment for field crops
Get PDFPublication history: Accepted - 25 June 2021; Published online - 13 July 2021.Autonomous equipment for crop production is on the
verge of technical and economic feasibility, but government
regulation may slow its adoption. Key regulatory
issues include requirements for on-site human supervision,
liability for autonomous machine error, and intellectual
property in robotic learning. As an example of
the impact of regulation on the economic benefits of
autonomous crop equipment, analysis from the United
Kingdom suggests that requiring 100% on-site human supervision almost wipes out the economic benefits of
autonomous crop equipment for small and medium
farms and increases the economies-of-scale advantage
of larger farms
The long-term response of lake nutrient and chlorophyll concentrations to changes in nutrient loading in Ireland's largest lake, Lough Neagh
Get PDFPublication history: Accepted - 11 December 2020; Published - 29 April 2021.The long-term response of chlorophyll-a (chl-a) to changing lake water nutrient concentrations
and increasing water temperature was investigated in Lough Neagh, a large, hypereutrophic lake in
Northern Ireland. Trends in external and internal nutrient loading and their relation to lake nutrient
concentrations were also established. Lake water concentrations of total P (TP) have increased since
the 1990s but were not correlated with catchment inputs, which showed no trend. The characteristics
of internal loading of P have changed since the mid-1990s, with an earlier and larger mass of P
released from the sediments each summer. Catchment inputs of total oxidised N (NOx) decreased
from the peak value of 10,186T/yr in 1995 to 5,396T/yr in 2011, coinciding with a reduction in
lake water concentrations. External inputs and lake concentrations of NOx were highly correlated
(R=0.88). Water temperature increased approximately 1C and was a predictor of variation in chl-a
from 1974 to 2012. After the peak chl-a concentration in 1993, dissolved inorganic N (DIN) also
became an important predictor, accounting for almost half of the 44% variance explained by a hierarchical
partition model. Decreasing log (DIN:TP) ratios suggest that N limitation of chl-a has become
more important in the lake recently.This research was funded by the DAERA, Northern
Ireland
Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer
Get PDFPublication history: Accepted - 8 October 2021; Published online - 30 October 2021.To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L−1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4°C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature.E.M. was supported by a grant from the Swiss State Secretariat for Education, Research and Innovation to Bas Ibelings and by supplementary funding from University of Geneva.
Leibniz Association.
H.P. was supported by the US National Science Foundation
(1840715, 1831096). A.C.’s work was funded by the Spanish Agencia
Estatal de Investigacion and EU funds through the project CLIMAWET
(CGL2015-69557-R). The collection of data for Lough Erne and Lough
Neagh were funded by the Department of Agriculture, Environment and
Rural Affairs, Northern Ireland.
Open access funding provided by Universite de Geneve
Invasions of ecological communities: Hints of impacts in the invader's growth rate
Get PDFPublication history: Accepted - 6 September 2021; Published - 11 October 2021.1. Theory in ecology and evolution often relies on the analysis of invasion processes,
and general approaches exist to understand the early stages of an invasion.
However, predicting the long-term
transformations of communities following an
invasion remains a challenging endeavour.
2. We propose a general analytical method that uses both resident community and
invader dynamical features to predict whether an invasion causes large long-term
impacts on the invaded community.
3. This approach reveals a direction in which classic invasion analysis, based on initial
invasion growth rate, can be extended. Indeed, we explain how the density dependence
of invasion growth, if properly defined, synthetically encodes the long-term
biotic transformations caused by an invasion, and therefore predicts its ultimate
outcome. This approach further clarifies how the density dependence of the invasion
growth rate is as much a property of the invading population as it is one of the
invaded community.
4. Our theory applies to any stable community model, and directs us towards new
questions that may enrich the toolset of invasion analysis, and suggests that indirect
interactions and dynamical stability are key determinants of invasion outcomes.J.-F.
A. and A.L.J. were supported by an
Irish Research Council Laureate Award IRCLA/2017/186. M.B.
was supported by the TULIP Laboratory of Excellence (ANR-10-
LABX-
41)
and by the BIOSTASES Advanced Grant, funded by the
European Research Council under the European Union's Horizon
2020 research and innovation programme (666971). G.B. was supported
by the Swedish Research Council (Vetenskapsrådet), grant
no. VR-2017-
05245.
Open access funding enabled and organized
by IRel
Dynamic Relationships among Phosphate Rock, Fertilisers and Agricultural Commodity Markets: Evidence from a Vector Error Correction Model and Directed Acyclic Graphs
Get PDFPublication history: Accepted - 13 August 2021; Published online - 24 August 2021.The finite supply of phosphate rock, as well as rising fertiliser prices, are key topics in the discussion around global food system resilience. Our paper contributes to this discussion by conducting an analysis of the dynamic causal relationships between phosphate rock, fertilisers, and wheat prices to provide insights on how farmers and policymakers might respond to phosphate rock supply shocks for sustainable and resilient food systems. The linkages between 147 monthly price observations spanning from March 2007 to April 2019 were analysed by combining Directed Acyclic Graphs (DAG), a recently developed modelling technique, and a Vector Error Correction Model (VECM). The findings suggest that there are five long-run cointegrating relationships between these three key components of the food supply chain. Price shocks to the phosphate rock market, over a two-year period had a knock-on positive impact on phosphorus fertiliser prices and to a lesser extent on wheat prices. Interestingly, an increase in wheat price had a sizeable impact on both fertiliser and phosphate rock prices, providing empirical evidence that increases in the price of phosphate rock are driven by demand factors, as well as supply factors.The study was conducted as part of the RePhoKus project “The role of Phosphorus in the Resilience and Sustainability of the UK food system” funded by the the Global Food Security's ‘Resilience of the UK Food System Programme’ with the UK's Biotechnology and Biological Science Research Council (BBSRC), the Economic and Social Research Council (ESRC), the Natural Environment Research Council (NERC), and the Scottish Government (Grant No. BB/R005842/1)
Local stability properties of complex, species-rich soil food webs with functional block structure
Get PDFPublication history: Accepted - 14 October 2021; Published online - 3 November 2021.Ecologists have long debated the properties that confer stability to complex, species-rich ecological networks. Species-level soil food webs are large and structured networks of central importance to ecosystem functioning. Here, we conducted an analysis of the stability properties of an up-to-date set of theoretical soil food web models that account both for realistic levels of species richness and the most recent views on the topological structure (who is connected to whom) of these food webs. The stability of the network was best explained by two factors: strong correlations between interaction strengths and the blocked, nonrandom trophic structure of the web. These two factors could stabilize our model food webs even at the high levels of species richness that are typically found in soil, and that would make random systems very unstable. Also, the stability of our soil food webs is well-approximated by the cascade model. This result suggests that stability could emerge from the hierarchical structure of the functional organization of the web. Our study shows that under the assumption of equilibrium and small perturbations, theoretical soil food webs possess a topological structure that allows them to be complex yet more locally stable than their random counterpart. In particular, results strongly support the general hypothesis that the stability of rich and complex soil food webs is mostly driven by correlations in interaction strength and the organization of the soil food web into functional groups. The implication is that in real-world food web, any force disrupting the functional structure and distribution pattern of interaction strengths (i.e., energy fluxes) of the soil food webs will destabilize the dynamics of the system, leading to species extinction and major changes in the relative abundances of species.TC was supported by the project SENSE (Structure and Ecological
Niche in the Soil Environment; EC FP7 –631399
–SENSE).
TC and
FdC were also supported by the NERC Grant Controls on the stability
of soils and their functioning under land use and climate change
(NE/M017036/1) as was RDB (NE/M017028/1). MÖ was supported
by the European Regional Development Fund [Centre of Excellence
EcolChange]
First Report of the Ash Sawfly, Tomostethus nigritus, Established on Fraxinus excelsior in the Republic of Ireland
Get PDFPublication history: Accepted - 15 December 2021; Published - 21 December 2021.Simple Summary: Ash sawfly, Tomostethus nigritus, larvae feed on the leaves of Fraxinus excelsior.
In the last 20 years, outbreaks of these insects have become more common, and they cause severe
defoliation of the tree crown. This pest is native to Europe, and it was recorded for the first time
on the island of Ireland in Belfast, Northern Ireland (UK) in 2016. This article is the first report of T.
nigritus in the Republic of Ireland (IE). Damaged leaves and larvae were observed on ash trees in
Co. Kildare in summer 2021. The larvae were collected and then identified using molecular analyses.
Similar damaged leaves were observed on trees in Co. Dublin, which showed mild defoliation of
the crown. However, severe defoliation of ash trees has also been recorded in Co. Meath in 2021.
No control treatments are available against the insects, and little is known about the cause of the
outbreaks. Severe outbreaks by T. nigritus could further affect the delicate situation that the Irish ash
tree population is currently facing caused by another severe antagonist of Fraxinus, the ash dieback
pathogen Hymenoscyphus fraxineus.
Abstract: This is the first report of the ash sawfly, Tomostethus nigritus, in the Republic of Ireland. We
observed defoliated leaves of Fraxinus excelsior L. and T. nigritus larvae at a forestry plantation in
Co. Kildare. Morphological observation of the larvae and DNA analysis using mitochondrial COI
barcoding confirmed the identification of this pest of ash.This research was funded by DAFM and DAERA grant number 2019R578, Nexcelsior: Next Steps in managing the impact of ash dieback project
Impact of paper bedding on lying behaviour and welfare in lactating dairy cows
Get PDFPublication history: Accepted - 1 April 2021; Published online - 8 April 2021.Lying is a highly motivated behaviour in dairy cows. The level of comfort provided by the lying surface not only
affects lying time, but can also affect several other aspects of welfare. We used a crossover design to compare
shredded paper and sawdust bedding in relation to lying behaviour, activity, lameness, integument damage,
cleanliness and productivity. Cubicles were bedded with a thin layer of bedding, which was replaced as necessary
to retain its hygienic state. Twenty-eight lactating Holstein-Friesian dairy cows were divided into two balanced
groups that experienced each bedding treatment for a 2 week period in opposing order. Paper bedding resulted in
significantly less time spent lying down (paper: 45 %, SD ± 6.7, sawdust: 48 %, SD ± 7.3, P < 0.01). Paper had a
more beneficial effect on lameness development than sawdust did (lameness decreased for eight cows and
increased for one cow whilst on paper, whereas it decreased for one cow and increased for ten cows whilst on
sawdust, P < 0.005). However, the magnitude of improvement in mobility score whilst on paper (0.5 points) was
small compared to the deterioration seen whilst on sawdust (1–2 points). Bedding adhesion tended to be slightly
increased during the paper bedding treatment (paper: 0.14 ± 0.16 SD, sawdust 0.03 ± 0.26 SD, P = 0.09). No
treatment effect was observed for lying frequency, the speed of transitions towards lying, pre-transition intention
movements, or the risk of collisions during the transition (P > 0.10). Furthermore, no significant effects on step
count, damage to the integument, cleanliness or milk yields were observed (P > 0.10). Slips were too rare overall
for analysis. These findings indicate that paper bedding and sawdust were mostly comparable in terms of impact
on behaviour, welfare and productivity when provided on a short-term basis. Future trials are recommended to
determine if treatment effects persist following prolonged exposure to paper bedding. Assessing the longitudinal
development of lameness and the long-term impact of reduced lying time will be essential.This work was supported by Re-Gen Waste Ltd
Proxy measures and novel strategies for estimating nitrogen utilization efficiency in dairy cattle
Get PDFPublication history: Accepted - 26 January 2021; Published online - 29 January 2021The efficiency with which dairy cows convert dietary nitrogen (N) to milk N is generally low (typically 25%). As a result, much of the N consumed is excreted in manure, from which N can be lost to the environment. Therefore there is increasing pressure to reduce N excretion and improve N use efficiency (NUE) on dairy farms. However, assessing N excretion and NUE on farms is difficult, thus the need to develop proximate measures that can provide accurate estimates of nitrogen utilisation. This review examines a number of these proximate measures. While a strong relationship exists between blood urea N and urinary N excretion, blood sampling is an invasive technique unsuitable for regular herd monitoring. Milk urea N (MUN) can be measured non-invasively, and while strong relationships exist between dietary crude protein and MUN, and MUN and urinary N excretion, the technique has limitations. Direct prediction of NUE using mid-infrared analysis of milk has real potential, while techniques such as near-infrared spectroscopy analysis of faeces and manure have received little attention. Similarly, techniques such as nitrogen isotope analysis, nuclear magnetic resonance spectroscopy of urine, and breath ammonia analysis may all offer potential in the future, but much research is still required.This research was funded by Department of Agriculture, Environment and Rural Affairs (DAERA) under grant number 19-1-16, by John Thompson and Sons Limited, and by Trouw Nutrition Limite