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T-Stór is Teagasc’s Open Access Repository, maintained by the Teagasc Library Service. Stór is the Gaelic word for Repository or Store or Warehouse, and T-Stór is an online “store” of Teagasc Research outputs and related documents. T-Stór collects preserves and makes freely available scholarly communication, including peer-reviewed articles, working papers and conference papers created by Teagasc researchers. Where material has already been published it is made available subject to the open-access policies of the original publishers. About Teagasc
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Distinct actions of the fermented beverage kefir on host behaviour, immunity and microbiome gut-brain modules in the mouseBackground Mounting evidence suggests a role for the gut microbiota in modulating brain physiology and behaviour, through bi-directional communication, along the gut-brain axis. As such, the gut microbiota represents a potential therapeutic target for influencing centrally mediated events and host behaviour. It is thus notable that the fermented milk beverage kefir has recently been shown to modulate the composition of the gut microbiota in mice. It is unclear whether kefirs have differential effects on microbiota-gut-brain axis and whether they can modulate host behaviour per se. Methods To address this, two distinct kefirs (Fr1 and UK4), or unfermented milk control, were administered to mice that underwent a battery of tests to characterise their behavioural phenotype. In addition, shotgun metagenomic sequencing of ileal, caecal and faecal matter was performed, as was faecal metabolome analysis. Finally, systemic immunity measures and gut serotonin levels were assessed. Statistical analyses were performed by ANOVA followed by Dunnett's post hoc test or Kruskal-Wallis test followed by Mann-Whitney U test. Results Fr1 ameliorated the stress-induced decrease in serotonergic signalling in the colon and reward-seeking behaviour in the saccharin preference test. On the other hand, UK4 decreased repetitive behaviour and ameliorated stress-induced deficits in reward-seeking behaviour. Furthermore, UK4 increased fear-dependent contextual memory, yet decreased milk gavage-induced improvements in long-term spatial learning. In the peripheral immune system, UK4 increased the prevalence of Treg cells and interleukin 10 levels, whereas Fr1 ameliorated the milk gavage stress-induced elevation in neutrophil levels and CXCL1 levels. Analysis of the gut microbiota revealed that both kefirs significantly changed the composition and functional capacity of the host microbiota, where specific bacterial species were changed in a kefir-dependent manner. Furthermore, both kefirs increased the capacity of the gut microbiota to produce GABA, which was linked to an increased prevalence in Lactobacillus reuteri. Conclusions Altogether, these data show that kefir can signal through the microbiota-gut-immune-brain axis and modulate host behaviour. In addition, different kefirs may direct the microbiota toward distinct immunological and behavioural modulatory effects. These results indicate that kefir can positively modulate specific aspects of the microbiota-gut-brain axis and support the broadening of the definition of psychobiotic to include kefir fermented foods. Video abstract.
In vitro screening of different Pseudomonas fluorescens isolates to study lytic enzyme production and growth inhibition during antagonism of Fusarium oxysporum f. sp. cumini, wilt causing pathogen of cuminLand plants exist in close association with bacterial and fungal microbes, where some associations can be pathogenic and others can be mutualistic/beneficial. One such relation exists between host plant, Cuminum cyminum L. (Cumin) and Fusarium oxysporum f. sp. cumini (Foc), the causal pathogen of cumin wilt and Pseudomonas fluorescens (Pf), where Pf acts as a bio-agent for inhibiting Foc and promoting plant growth of cumin. In this study, antagonism by 10 different Pf isolates against Foc was studied under laboratory conditions through percent growth inhibition and biochemical mechanisms. Among these Pf isolates, Pf-5 exhibited the highest in vitro growth inhibition (82.51%). A positive correlation was observed between percent growth inhibition and specific activities of hydrolytic enzymes, chitinase, β-1, 3 glucanase, and protease, where a negative correlation was observed with cell wall degrading enzymes, cellulase and polygalacturonase. To conclude, isolate Pf-5 could be a potential biocontrol agent for Fusarium wilt disease of cumin.
Investigating the impact of varying levels of inventory data detail on private sector harvest forecastingA comparison was made between four methods of generating roundwood production forecasts for private sector forests in Ireland which used varying levels of inventory data as inputs into the production Model. Two methods were based on stand variables: the Irish Dynamic Yield Model (IDYM) method and the General Yield Class (GYC) method. The other two methods were based on site variables used to derive predictions of productivity from climate and map-based data and include a local prediction (LPYC) and a national prediction of yield class (NPYC), the latter the same as that used in the All Ireland Roundwood Production Forecast 2016-2035 (Phillips et al. 2016). To determine the reliability of predictions for an individual stand, field measurements of yield class (GYC) were compared with the predictions of yield class derived using the NPYC and LPYC methods for 52 privately-owned stands of Sitka spruce in the north-west of Ireland. The prediction of yield class using the NPYC method had a low probability of agreement with GYC, with a large bias to under-predict yield class. The LPYC method had a higher probability of agreement and lower bias indicating a better assessment of local productivity. To assess the impact of the various productivity estimates on roundwood production forecasts, separate roundwood forecasts for the period 2016- 2035 were generated. The forecast produced using the NPYC method was used as a baseline for comparison purposes. As expected, the under-prediction of yield class using the NPYC method produced the lowest volume production estimate (318,454 m3) for the forecast period. Both the GYC and LPYC methods resulted in a significant increase in estimated volume production of between 25% and 29% over the baseline. The IDYM method provided the highest estimate of volume production (432,000 m3) for the forecast period, an increase of 35% over the baseline. The increased output predicted using the IDYM method is explained by the inclusion of stocking and basal area data, which more accurately reflected the increased growing stock of private forests than yield data derived using Forestry Commission yield models based on prescribed management. The increases in productivity associated with the use of LPYC, GYC and IDYM methods had the effect of producing shorter rotations and resulted in an increase in the area clearfelled and associated volume production. Perhaps more importantly, the timing of volume production was affected by using more accurate methods to assess productivity (i.e. LPYC, GYC, IDYM), owing to a higher yield-age profile of stands compared to those assessed using the NPYC predictions. The findings point to a possible under-estimation of the productivity for private stands in the All Ireland Roundwood Production Forecast and have implications for the timing of the forecasted volume which could be brought forward by 5 to 6 years. In the absence of field or aerial laser measurement of height and age, the use of the LPYC method is recommended for future private sector roundwood producion forecasts.
Self-association of bovine β-casein as influenced by calcium chloride, buffer type and temperatureThe aim of this study was to investigate the aggregation behaviour of a pure β-casein (β-CNpure) and a β-casein concentrate (β-CNconc) as a function of temperature, buffer type (pH 6.8) and the presence of CaCl2. The particle size distribution and turbidity of β-casein (β-CN) dispersions were measured by dynamic light-scattering (DLS) and UV/vis spectroscopy between 4 and 55 °C. Upon heating (4–55 °C), the particle size of both β-CN samples increased, indicating self-association via hydrophobic interactions. It was shown that the self-association of β-CN increased with increasing β-CN concentration and that β-CNpure self-associated at significantly lower concentration than β-CNconc. Both turbidity and particle size measurements showed that the β-CN samples had similar aggregation behaviour in water and imidazole buffer (pH 6.8) but differed in sodium phosphate buffer (pH 6.8), especially at higher ionic calcium concentrations. Fourier Transform Infrared (FTIR) spectroscopy revealed very little change in the secondary structure of β-CN during heating (4–55 °C). The microstructure of β-CN aggregates was monitored during heating from 10 to 55 °C, followed by cooling to 10 °C, using polarised light microscopy. Spherical and heterogeneous aggregates were observed when heated at temperatures above 37 °C, which were reversible upon cooling. This study confirmed that β-CN undergoes self-association on heating that reverses upon cooling, with the aggregation process being highly dependent on the purity of β-CN, the solvent type and the presence of ionic calcium.
Structural mechanism and kinetics of in vitro gastric digestion are affected by process-induced changes in bovine milkBovine milk is commonly exposed to processing, which can alter the structure, biochemical composition, physico-chemical properties and sensory quality. While many of these changes have been studied extensively, little is known about their effect on digestive behaviour. In this study, heat treatments of pasteurisation at 72 °C for 15 s or Ultra-High-Temperature (UHT) treatment at 140 °C for 3 s and homogenisation at pilot-plant scale were applied to whole milk. The gastric behaviour was investigated using a recently developed semi-dynamic adult in vitro model. The emptied digesta were analysed to assess the nutrient delivery kinetics, changes in microstructure and protein digestion. All samples showed protein aggregation and coagulum formation within the first 15 min of gastric digestion at which time the pH ranged from 5.5 to 6. Homogenised samples creamed regardless of heat treatment, whereas all non-homogenised samples exhibited sedimentation. The consistency of the coagulum of the heated samples was more fragmented compared to those of the non-heated samples. Rheological analysis showed that the higher the temperature of the heat treatment, the softer the obtained coagulum and the higher the protein hydrolysis at the end of digestion. The study also confirmed that gastric emptying of caseins from milk is delayed due to coagulation in the stomach, while β-lactoglobulin was emptied throughout the gastric phase, except for UHT-treated milk. The gastric behaviour also had an impact on the lipid and protein content of the emptied chyme. The homogenised samples seemed to release more nutrients at the end of gastric digestion