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Sweeney, Torres
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Sweeney, Torres
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Sweeney, Torres
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Now showing 1 - 10 of 15
- PublicationUltrasonic extraction(Teagasc, 2018-08-08)
; ; ; Found in seaweed, fucoidans have many beneficial properties, but extracting them from the plant has proved difficult. UCD and TEAGASC researchers looked at one promising technology.66 - PublicationEffect of seasons on the proximate composition of Laminaria hyperborea from Irish Atlantic coast(2018-10-27)
; ; ; ; This study aimed to analyze the seasonal variation in the proximate composition of Laminaria hyperborea collected in 2016 and 2017, off the west coast of Ireland.27 - PublicationIn vitro effects of seaweed extracts on intestinal commensals and pathogens of weaned piglets(Microbiology Society, 2018-06-21)
; ; ; ; ; While the inclusion of certain seaweed extracts in weaner piglet diets leads to a beneficial gut microbial profile, the mode of action is not known. The aim of this study was to evaluate the prebiotic and antimicrobial potential of Laminaria digitata and Ascophylum nodosum extracts in vitro. Both extracts were two-fold diluted from 2 mg/ml to 0.25 mg/ml. The following strains were used at 106 -107 colonyforming unit(CFU)/ml concentrations: Lactobacillus plantarum, L. reuteri, Bifidobacterium thermophilum, Enterotoxigenic Escherichia coli O149 and Salmonella enterica ser Typhimurium PT12. Each concentration of each extract and controls (0 mg/ml) were incubated for 18 h at 37 °C aerobically or anaerobically (B. thermophilum). Final bacterial concentrations were determined by spread plating. All experiments were carried out with technical replicates on three independent occasions. All data were logarithmically transformed and analysed using the PROC GLM (SAS 9.4). The L. digitata extract increased B. thermophilum 0.7 LogCFU/ml at 0.25 mg/ml (P<0.05) and ≥1 LogCFU/ml from 0.5-2 mg/ml (P<0.05), with no effect on lactobacilli. The A. nodosum extract increased B. thermophilum up to 0.9 LogCFU/ml at all concentrations tested (P<0.05). Additionally, a 0.2 LogCFU/ml increase of L. reuteri and L. plantarum was observed at 2 mg/ml (P<0.05) and 1mg/ml (P<0.05), respectively. Both extracts displayed no antimicrobial activity against ETEC or S. Typhimurium. In conclusion, both extracts exhibited bifidogenic activity in vitro, with an additional slight increase of Lactobacillus spp. for A. nodosum, indicating a prebiotic potential.38 - PublicationChito-Oligosaccharide Inhibits the De-Methylation of a CpG Island within the Leptin (LEP) Promoter during Adipogenesis of 3T3-L1 Cells(Public Library of Science, 2013-03-27)
; ; ; Chito-oligosaccharide (COS) is a natural bioactive compound, which has been shown to suppress lipid metabolic genes and lipid accumulation in differentiating adipocytes. Leptin has been identified as a key regulator of energy homeostasis and is known to be under epigenetic regulation during adipogenesis. Hence, the first objective of this experiment was to compare leptin gene (LEP) expression and leptin secretion during the different stages of adipogenesis and to investigate the effect of COS on these processes. As COS inhibited LEP expression during adipogenesis, the second aim was to investigate the methylation dynamics of a ¿CpG¿ island in the proximal region of the LEP promoter during adipogenesis and to determine the effect of COS on this process. Mouse 3T3-L1 cells were stimulated to differentiate in the absence or presence of COS and the levels of leptin mRNA and protein were evaluated on days 0, 2, 4 and 6 post-induction of differentiation (PID). The extent of de-methylation of six CpG sites was evaluated. LEP mRNA transcript and protein could not be detected on either day 0PID or 2PID. In contrast, both were detected on day 4PID (P<0.05) and 6PID (P<0.001) and both were inhibited by COS (P<0.001). Of the six CpG sites analyzed, CpG_52, CpG_62 and CpG_95 became 11.5, 5.0 and 5.0% de-methylated between day 2PID and 6PID, respectively. COS blocked this de-methylation event at CpG_52 (P<0.001), CpG_62 (P<0.01) and CpG_95 (P<0.01) on day 6PID. These data suggest that COS can have an epigenetic effect on differentiating adipocytes, a novel biological function of COS which has potential applications for the manipulation of leptin gene expression, adipogenesis, and conditions within the metabolic syndrome spectrum.335Scopus© Citations 7 - PublicationExploring ultrasound-assisted extraction to recover high valuable polysaccharides from brown macroalgae and its related antioxidant activities(2018-10-27)
; ; ; ; This study aimed to optimize the ultrasound-assisted extraction (UAE) parameters of temperature, time and amplitude on the yields of fucose and glucans and their antioxidant activities (FRAP and DPPH) of extracts from Laminaria digitata and to evaluate the application of these optimum UAE parameters in other brown macroalgae (L. hyperborea and Ascophyllum nodosum).23 - PublicationEffects of extraction method on the prebiotic potential of Ascophylum nodosum extracts(Microbiological Society, 2018-06-28)
; ; ; ; ; Seaweed-derived bioactive compounds exhibit various beneficial activities in humans and animals. A factor influencing their concentrations, and subsequent bioactivity, is the extraction method. Our aim was to evaluate the in vitro prebiotic potential of three differently-extracted Ascophylum nodosum samples. The samples were produced using either solid-liquid extraction with water (AN-W), or ethanol (AN-EtOH) as solvent or high pressure-assisted extraction with water as solvent (AN-HPW). All extracts were two-fold diluted from 2 mg/ml to 0.25 mg/ml. Lactobacillus plantarum (LP), L. reuteri (LR) and Bifidobacterium thermophilum (BT) were used at 106 -107 colony-forming unit(CFU)/ml. Each concentration of each extract and controls (0 mg/ml) were incubated for 18 h at 37 °C aerobically or anaerobically (BT). Final bacterial concentrations were determined by spread plating. All experiments were carried out in triplicate with technical replicates. All data were logarithmically transformed and analysed using PROC GLM (SAS 9.4). AN-HPW increased BT (≤0.9 LogCFU/ml, P<0.05) at all concentrations and LR and LP (0.2 LogCFU/ml, P<0.05) at 2 mg/ml and 1mg/ml, respectively. AN-W increased BT (≤0.6 LogCFU/ml, P<0.05) at 1-2mg/ml, but decreased both lactobacilli; LP ≤0.7 LogCFU/ml and LR ≤5.4 LogCFU/ml at all concentrations (P<0.05). AN-EtOH increased LP (≤0.7 LogCFU/ml, P<0.05), but reduced LR (≤5.7 LogCFU/ml, P<0.05) at all concentrations and BT (≤4 LogCFU/ml, P<0.05) at 1-2 mg/ml. In conclusion, the extraction method influenced the prebiotic potential of the A. nodosum extracts in vitro with AN-HPW being the most promising.23 - PublicationEnhancing the extraction of polysaccharides and antioxidants from macroalgae using sequential hydrothermal-assisted extraction followed by ultrasound and thermal technologies(MDPI, 2019-08-05)
; ; ; ; Fucose sulphated polysaccharides (FSPs) and glucans have recently attracted the attention of the scientific community due to their wide range of biological activities. Both polysaccharides should ideally be selectively extracted using innovative technologies with high extraction efficiency. This study aims to: (1) Optimise the extraction variables used in hydrothermal-assisted extraction (HAE) to obtain high yields of FSPs, total glucans, and antioxidants from Laminaria hyperborea; (2) to apply these optimised protocols to other brown macroalgae; and (3) to explore the application of ultrasound and thermal technologies to increase the recovery of polysaccharides from the residual biomass. Box-Behnken design (three-factor, four-levels) was employed to optimise the HAE variables, and principal component analysis was used to evaluate the recovery of polysaccharides from the residual biomass. The optimal HAE conditions were 120 ◦C, 80.9 min, and 12.02 mL/g macroalgae from L. hyperborea. The best sequential application of ultrasound and thermal treatment achieved an additional 2971.7 ± 61.9 mg fucose/100 g dried macroalgal residue (dmr) from Ascophyllum nodosum and 908.0 ± 51.4 mg total glucans/100 g dmr from L. hyperborea macroalgal residues.115Scopus© Citations 47 - PublicationEffect of β-glucanase and β-xylanase enzyme supplemented barley diets on nutrient digestibility, growth performance and expression of intestinal nutrient transporter genes in finisher pigs(Elsevier, 2018-04)
; ; ; ; ; ; ; The study investigated the effect of dietary supplementation of an enzyme mix (β-glucanase and β-xylanase) to barley based diets that had different chemical compositions achieved through different agronomical conditions on growth performance, nutrient digestibility and intestinal nutrient transporters. Ninety-six pigs (44.7 kg (SD 4.88)) were assigned to one of four dietary treatments. The treatments were as follows: (T1) low quality barley diet, (T2) low quality barley diet supplemented with β-glucanase and β-xylanase enzyme supplement, (T3) high quality barley diet and (T4) high quality barley diet supplemented with β-glucanase and β-xylanase enzyme supplement. The inclusion of barley was 500 g/kg. There was an interaction between barley type and enzyme supplementation on average daily gain (ADG) and average daily feed intake (ADFI) (P < 0.05). Pigs offered the low quality barley diet supplemented with enzymes had an increase in both ADG and ADFI compared to the low quality barley diet only. However, there was no response to enzyme inclusion in the high quality barley diet. Pigs offered the low quality barley diet with enzymes had a higher coefficient of apparent total tract digestibility (CATTD) of gross energy (GE) compared to the low quality barley diet only (P < 0.05). However, the increase in the high quality barley diet with enzyme supplementation was not as great as with the low quality barley diet. Pigs offered the low quality barley had an upregulation in the expression of the ghrelin gene (GHRL) in the jejunum compared to pigs offered the high quality barley diet (P < 0.05). There was a barley × enzyme interaction observed for the expression of the cluster of differentiation gene (CD36) in the duodenum and the peptide transporter 1 gene (PEPT1/SLC15A1) and sodium-glucose linked transporter 1 gene (SGLT1/SLC5A1) in the ileum (P < 0.01). Pigs offered the high quality barley diet with enzymes had increased expression of CD36, PEPT1/SLC15A1 and SGLT1/SLC5A1 compared to the high quality barley diet alone. However the low quality barley diet with enzymes down regulated the expression of CD36, PEPT1/SLC15A1 and SGLT1/SLC5A1 compared to the low quality barley diet alone. In conclusion, offering a low quality barley diet supplemented with an enzyme mix improved ADG, ADFI and nutrient digestibility as well as modifying the expression of CD36, PEPT1/SLC15A1 and SGLT1/SLC5A1. The inclusion of an enzyme mix to the high quality barley diet improved nutrient digestibility and caused an upregulation in the expression of CD36, PEPT1/SLC15A1 and SGLT1/SLC5A1 but it did not improve animal performance.333Scopus© Citations 15 - PublicationPolysaccharides from macroalgae: Recent advances, innovative technologies and challenges in extraction and purification(Elsevier, 2016-11)
; ; ; Polysaccharides obtained from macroalgae have promising prospects and could contribute greatly to the future of a marine based bio-economy. Specifically, laminarin and fucoidan from brown macroalgae have a wide variety of potential industrial applications including functional foods and nutraceuticals, due to their broad range of biological activities. These beneficial biological activities are related to the chemical composition and structure of the macroalgal polysaccharides. The molecular weight, monosaccharide composition and sulphate content of these polysaccharides could be influenced by both macroalgal biology (i.e. variations in polysaccharide composition due to macroalgae species and their biological cycle) and different extraction/purification techniques employed to obtain polysaccharide enriched products (i.e. de-sulphation or fragmentation of sulphated polysaccharides). This review focuses on the extraction and purification methods for the macroalgal polysaccharides laminarin and fucoidan used in the recent literature. The application of innovative extraction technologies (such as ultrasound, microwave and enzyme-assisted extractions), as well as new purification techniques (i.e. membrane separation), are also discussed together with the challenges concerning molecule structure-function relationship and macroalgal variability.2494Scopus© Citations 175 - PublicationExtraction and yield optimisation of fucose, glucans and associated antioxidant activities from laminaria digitata by applying response surface methodology to high intensity ultrasound-assisted extraction(MDPI, 2018-07-30)
; ; ; ; The objectives of this study were to employ response surface methodology (RSM) to investigate and optimize the effect of ultrasound-assisted extraction (UAE) variables, temperature, time and amplitude on the yields of polysaccharides (fucose and total glucans) and antioxidant activities (ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity (DPPH)) from Laminaria digitata, and to explore the suitability of applying the optimum UAE conditions for L. digitata to other brown macroalgae (L. hyperborea and Ascophyllum nodosum). The RSM with three-factor, four-level Box-Behnken Design (BBD) was used to study and optimize the extraction variables. A second order polynomial model fitted well to the experimental data with R2 values of 0.79, 0.66, 0.64, 0.73 for fucose, total glucans, FRAP and DPPH, respectively. The UAE parameters studied had a significant influence on the levels of fucose, FRAP and DPPH. The optimised UAE conditions (temperature = 76 ◦C, time = 10 min and amplitude = 100%) achieved yields of fucose (1060.7 ± 70.6 mg/100 g dried seaweed (ds)), total glucans (968.6 ± 13.3 mg/100 g ds), FRAP (8.7 ± 0.5 µM trolox/mg freeze-dried extract (fde)) and DPPH (11.0 ± 0.2%) in L. digitata. Polysaccharide rich extracts were also attained from L. hyperborea and A. nodosum with variable results when utilizing the optimum UAE conditions for L. digitata.143Scopus© Citations 53