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M Scortichini - One of the best experts on this subject based on the ideXlab platform.
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frost promotes the pathogenicity of pseudomonas syringae pv Actinidiae in Actinidia chinensis and a deliciosa plants
Plant Pathology, 2014Co-Authors: P Ferrante, M ScortichiniAbstract:Frost occurs in all major areas of cultivation, presenting a threat for the production of kiwifruit crops worldwide. A series of experiments were performed on 1-year-old, potted plants or excised twigs of Actinidia chinensis and A. deliciosa to verify whether strict relationships exist between bacterial canker outbreaks from Pseudomonas syringae pv. Actinidiae (Psa) attacks and the occurrence of autumn and winter frost events. The association between the occurrence of autumn frost and the sudden outbreak of bacterial canker in A. chinensis in central Italy has been confirmed. Both autumn and winter frosts promote Psa multiplication in the inoculated twigs of both species. The day after the frost, reddish exudates oozing from the inoculation sites were consistently observed in both species, and Psa was re-isolated in some cases. During the thawing of both A. deliciosa and A. chinensis twigs, the 2-cm upward and downward migration of Psa from the inoculation site was observed within 3 min, and the leaves were consistently colonized with the pathogen. A consistent brown discoloration, accompanied with a sour-sap odour, was observed throughout the length of the excised twigs of both Actinidia species after Psa inoculation and winter frost. Psa inoculation induced a remarkably higher necrosis in excised twigs that were not frozen compared with P. s. pv. syringae inoculation. Antifreeze protection using irrigation sprinklers did not influence the short-term period of Psa and P. s. pv. syringae multiplication in both A. deliciosa and A. chinensis twigs. Thus, the damage from frost, freeze thawing and the accumulation of Psa in Actinidia twigs promotes the migration of the pathogen within and between the orchards. Taken together, the results obtained in this study confirmed that A. deliciosa is more frost tolerant than A. chinensis, autumn frosts are more dangerous to these crops than winter frosts, and in the absence of Psa, young kiwifruit plants remain sensitive to frost.
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proteomic changes in Actinidia chinensis shoot during systemic infection with a pandemic pseudomonas syringae pv Actinidiae strain
Journal of Proteomics, 2013Co-Authors: Milena Petriccione, Ilaria Di Cecco, Andrea Scaloni, Simona Arena, M ScortichiniAbstract:A pandemic, very aggressive population of Pseudomonas syringae pv. Actinidiae is currently causing severe economic losses to kiwifruit crops worldwide. Upon leaf attack, this Gram-negative bacterium systemically reaches the plant shoot in a week period. In this study, combined 2-DE and nanoLC-ESI-LIT-MS/MS procedures were used to describe major proteomic changes in Actinidia chinensis shoot following bacterial inoculation in host leaf. A total of 117 differentially represented protein spots were identified in infected and control shoots. Protein species associated with plant defence, including type-members of the plant basal defence, pathogenesis, oxidative stress and heat shock, or with transport and signalling events, were the most represented category of induced components. Proteins involved in carbohydrate metabolism and photosynthesis were also augmented upon infection. In parallel, a bacterial outer membrane polypeptide component was identified in shoot tissues, whose homologues were already linked to bacterial virulence in other eukaryotes. Semiquantitative RT-PCR analysis confirmed expression data for all selected plant gene products. All these data suggest a general reprogramming of shoot metabolism following pathogen systemic infection, highlighting organ-specific differences within the context of a general similarity with respect to other pathosystems. In addition to present preliminary information on the molecular mechanisms regulating this specific plant-microbe interaction, our results will foster future proteomic studies aimed at characterizing the very early events of host colonization, thus promoting the development of novel bioassays for pathogen detection in kiwifruit material.
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pseudomonas syringae pv Actinidiae draft genomes comparison reveal strain specific features involved in adaptation and virulence to Actinidia species
PLOS ONE, 2011Co-Authors: Simone Marcelletti, Milena Petriccione, Patrizia Ferrante, Giuseppe Firrao, M ScortichiniAbstract:A recent re-emerging bacterial canker disease incited by Pseudomonas syringae pv. Actinidiae (Psa) is causing severe economic losses to Actinidia chinensis and A. deliciosa cultivations in southern Europe, New Zealand, Chile and South Korea. Little is known about the genetic features of this pathovar. We generated genome-wide Illumina sequence data from two Psa strains causing outbreaks of bacterial canker on the A. deliciosa cv. Hayward in Japan (J-Psa, type-strain of the pathovar) and in Italy (I-Psa) in 1984 and 1992, respectively as well as from a Psa strain (I2-Psa) isolated at the beginning of the recent epidemic on A. chinensis cv. Hort16A in Italy. All strains were isolated from typical leaf spot symptoms. The phylogenetic relationships revealed that Psa is more closely related to P. s. pv. theae than to P. avellanae within genomospecies 8. Comparative genomic analyses revealed both relevant intrapathovar variations and putative pathovar-specific genomic regions in Psa. The genomic sequences of J-Psa and I-Psa were very similar. Conversely, the I2-Psa genome encodes four additional effector protein genes, lacks a 50 kb plasmid and the phaseolotoxin gene cluster, argK-tox but has acquired a 160 kb plasmid and putative prophage sequences. Several lines of evidence from the analysis of the genome sequences support the hypothesis that this strain did not evolve from the Psa population that caused the epidemics in 1984–1992 in Japan and Italy but rather is the product of a recent independent evolution of the pathovar Actinidiae for infecting Actinidia spp. All Psa strains share the genetic potential for copper resistance, antibiotic detoxification, high affinity iron acquisition and detoxification of nitric oxide of plant origin. Similar to other sequenced phytopathogenic pseudomonads associated with woody plant species, the Psa strains isolated from leaves also display a set of genes involved in the catabolism of plant-derived aromatic compounds.
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clonal outbreaks of bacterial canker caused by pseudomonas syringae pv Actinidiae on Actinidia chinensis and a deliciosa in italy
Journal of Plant Pathology, 2011Co-Authors: Simone Marcelletti, M ScortichiniAbstract:A total of 28 representative Pseudomonas syringae pv. Actinidiae strains isolated from all Italian regions (Emilia- Romagna, Latium, Piedmont, Veneto) where outbreaks of bacterial canker of kiwifruit (Actinidia deliciosa) and yellow kiwifruit (A. chinensis) were observed in 2008-2010, were assessed using repetitive-sequence PCR (rep-PCR) with ERIC and BOX primer sets and multilocus sequence typing (MLST) using gapA, gltA, gyrB and rpoD genes. The 2.3 kb sequences obtained from MLST were analyzed by means of mathematicalstatistical tests to infer the gene polymorphism and the genetic structure of the strains. Both primer sets used in rep-PCR indicated an overall identity among all 28 P.s. pv. Actinidiae strains irrespective of the host plant and cultivar from where they were isolated, as well as of the region or year of isolation. In addition, MLST revealed a low gene polymorphism. A clonal structure and neutral selection were inferred for the P. s. pv. Actinidiae strains currently causing severe epidemics on A. chinensis and A. deliciosa in Italy. This indicates that they originated, most probably, from a single or very few introductions of latently infected kiwifruit propagative material, even though the possibility cannot be ruled out that cells of the pathogen already present in Italy may have mutated.
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molecular and phenotypic features of pseudomonas syringae pv Actinidiae isolated during recent epidemics of bacterial canker on yellow kiwifruit Actinidia chinensis in central italy
Plant Pathology, 2010Co-Authors: Patrizia Ferrante, M ScortichiniAbstract:Pseudomonas syringae pv. Actinidiae (Psa) was identified as the causal agent of severe epidemics of bacterial canker on Actinidia chinensis (yellow kiwifruit) in central Italy occurring during 2008–9. A total of 101 strains were obtained from infected leaves, twigs, branches and trunks of cvs Hort16A, Jin Tao and CK3. Outbreaks were also found on A. deliciosa cv. Hayward. A representative set of 21 strains were compared with other Psa strains isolated from previous outbreaks in Japan and Italy as well as with P. s. pv. syringae strains obtained from A. chinensis and with strains of genomospecies 8. Repetitive-sequence PCR (rep-PCR) typing using BOX and ERIC primer sets revealed that all Psa strains obtained during 2008–9 showed the same fingerprinting profile. This profile, however, was different from those of strains previously isolated in Japan and Italy. Multilocus sequence typing (MLST) of gapA, gltA, gyrB and rpoD revealed a higher genetic variability among the strains than rep-PCR, with some of them showing the same sequence pattern although isolated from different areas, cultivars and years. None of the recently obtained strains possessed genes coding for phaseolotoxin or coronatine, and all had an effector protein, namely hopA1, differentiating them from the strains causing past outbreaks in Japan and Italy. All isolates were inhibited in vitro by copper-based compounds, antibiotics, geraniol, citronellol and by a chitin-based organic compound. The recent epidemics found in central Italy on yellow kiwifruit appear to have been caused by a different Psa population than those previously recorded in Japan, South Korea and Italy.
Jia-ren Liu - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of antioxidant and antiproliferative properties of three Actinidia (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) extracts in vitro.
International journal of molecular sciences, 2012Co-Authors: Li-li Zuo, Zhenyu Wang, Zi-luan Fan, Shuang-qi Tian, Jia-ren LiuAbstract:The total phenolic content, total flavonoid content, vitamin C content, and antioxidant activities of ethanol extracts from different kiwifruit varieties (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) were determined in this study. Multiple scavenging activity assays including the hydroxyl radical, O2−·radical, DPPH, and the ABTS+ radical scavenging activity assays were used to identify the antioxidant activities of Actinidia extracts. The cell viability of HepG2 and HT-29 cells was also examined in this study. The results demonstrated that the Actinidia kolomikta extract had a higher antioxidant activity than the other two Actinidia extracts. There is a positive correlation between antioxidant activity and the polyphenols and vitamin C content in all three extracts (R2 ≥ 0.712, p < 0.05). The Actinidia arguta extract had the highest inhibitory effect on HepG2 and HT-29 cell growth. These results provide new insight into the health functions of fruit and demonstrate that Actinidia extracts can potentially have health benefits.
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Evaluation of Antioxidant and Antiproliferative Properties of Three <em>Actinidia</em> (<em>Actinidia</em> <em>kolomikta</em>, <em>Actinidia arguta</em>, <em>Actinidia</em> <em>chinens
MDPI AG, 2012Co-Authors: Jia-ren Liu, Zi-luan Fan, Zhenyu Wang, Shuang-qi Tian, Li-li ZuoAbstract:The total phenolic content, total flavonoid content, vitamin C content, and antioxidant activities of ethanol extracts from different kiwifruit varieties (<em>Actinidia</em> <em>kolomikta</em>, <em>Actinidia arguta</em>, <em>Actinidia</em> <em>chinensis</em>) were determined in this study. Multiple scavenging activity assays including the hydroxyl radical, O<sub>2</sub><sup>−</sup>·radical, DPPH, and the ABTS<sup>+</sup> radical scavenging activity assays were used to identify the antioxidant activities of <em>Actinidia</em> extracts. The cell viability of HepG2 and HT-29 cells was also examined in this study. The results demonstrated that the <em>Actinidia kolomikta</em> extract had a higher antioxidant activity than the other two <em>Actinidia</em> extracts. There is a positive correlation between antioxidant activity and the polyphenols and vitamin C content in all three extracts (<em>R</em><sup>2</sup> ≥ 0.712, <em>p</em><em> </em>< 0.05). The <em>Actinidia arguta</em> extract had the highest inhibitory effect on HepG2 and HT-29 cell growth. These results provide new insight into the health functions of fruit and demonstrate that <em>Actinidia</em> extracts can potentially have health benefits
Li-li Zuo - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of antioxidant and antiproliferative properties of three Actinidia (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) extracts in vitro.
International journal of molecular sciences, 2012Co-Authors: Li-li Zuo, Zhenyu Wang, Zi-luan Fan, Shuang-qi Tian, Jia-ren LiuAbstract:The total phenolic content, total flavonoid content, vitamin C content, and antioxidant activities of ethanol extracts from different kiwifruit varieties (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) were determined in this study. Multiple scavenging activity assays including the hydroxyl radical, O2−·radical, DPPH, and the ABTS+ radical scavenging activity assays were used to identify the antioxidant activities of Actinidia extracts. The cell viability of HepG2 and HT-29 cells was also examined in this study. The results demonstrated that the Actinidia kolomikta extract had a higher antioxidant activity than the other two Actinidia extracts. There is a positive correlation between antioxidant activity and the polyphenols and vitamin C content in all three extracts (R2 ≥ 0.712, p < 0.05). The Actinidia arguta extract had the highest inhibitory effect on HepG2 and HT-29 cell growth. These results provide new insight into the health functions of fruit and demonstrate that Actinidia extracts can potentially have health benefits.
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Evaluation of Antioxidant and Antiproliferative Properties of Three <em>Actinidia</em> (<em>Actinidia</em> <em>kolomikta</em>, <em>Actinidia arguta</em>, <em>Actinidia</em> <em>chinens
MDPI AG, 2012Co-Authors: Jia-ren Liu, Zi-luan Fan, Zhenyu Wang, Shuang-qi Tian, Li-li ZuoAbstract:The total phenolic content, total flavonoid content, vitamin C content, and antioxidant activities of ethanol extracts from different kiwifruit varieties (<em>Actinidia</em> <em>kolomikta</em>, <em>Actinidia arguta</em>, <em>Actinidia</em> <em>chinensis</em>) were determined in this study. Multiple scavenging activity assays including the hydroxyl radical, O<sub>2</sub><sup>−</sup>·radical, DPPH, and the ABTS<sup>+</sup> radical scavenging activity assays were used to identify the antioxidant activities of <em>Actinidia</em> extracts. The cell viability of HepG2 and HT-29 cells was also examined in this study. The results demonstrated that the <em>Actinidia kolomikta</em> extract had a higher antioxidant activity than the other two <em>Actinidia</em> extracts. There is a positive correlation between antioxidant activity and the polyphenols and vitamin C content in all three extracts (<em>R</em><sup>2</sup> ≥ 0.712, <em>p</em><em> </em>< 0.05). The <em>Actinidia arguta</em> extract had the highest inhibitory effect on HepG2 and HT-29 cell growth. These results provide new insight into the health functions of fruit and demonstrate that <em>Actinidia</em> extracts can potentially have health benefits
Milena Petriccione - One of the best experts on this subject based on the ideXlab platform.
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reference gene selection for normalization of rt qpcr gene expression data from Actinidia deliciosa leaves infected with pseudomonas syringae pv Actinidiae
Scientific Reports, 2015Co-Authors: Milena Petriccione, Francesco Mastrobuoni, Luigi Zampella, Marco ScortichiniAbstract:Normalization of data, by choosing the appropriate reference genes (RGs), is fundamental for obtaining reliable results in reverse transcription-quantitative PCR (RT-qPCR). In this study, we assessed Actinidia deliciosa leaves inoculated with two doses of Pseudomonas syringae pv. Actinidiae during a period of 13 days for the expression profile of nine candidate RGs. Their expression stability was calculated using four algorithms: geNorm, NormFinder, BestKeeper and the deltaCt method. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and protein phosphatase 2A (PP2A) were the most stable genes, while β-tubulin and 7s-globulin were the less stable. Expression analysis of three target genes, chosen for RGs validation, encoding the reactive oxygen species scavenging enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD) and catalase (CAT) indicated that a combination of stable RGs, such as GAPDH and PP2A, can lead to an accurate quantification of the expression levels of such target genes. The APX level varied during the experiment time course and according to the inoculum doses, whereas both SOD and CAT resulted down-regulated during the first four days, and up-regulated afterwards, irrespective of inoculum dose. These results can be useful for better elucidating the molecular interaction in the A. deliciosa/P. s. pv. Actinidiae pathosystem and for RGs selection in bacteria-plant pathosystems.
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proteomic analysis of the Actinidia deliciosa leaf apoplast during biotrophic colonization by pseudomonas syringae pv Actinidiae
Journal of Proteomics, 2014Co-Authors: Milena Petriccione, Ilaria Di Cecco, Anna Maria Salzano, Andrea Scaloni, Marco ScortichiniAbstract:Abstract For plant pathogenic bacteria, adaptation to the apoplast is considered as key in the establishment of the parasitic lifestyle. Pseudomonas syringae pv. Actinidiae (Psa), the causal agent of the bacterial canker of kiwifruit, uses leaves as the entry site to colonize plants. Through a combined approach based on 2-DE, nanoLC-ESI-LIT-MS/MS and quantitative PCR, we investigated Psa colonization of the Actinidia deliciosa “Hayward” leaf apoplast during the bacterial biotrophic phase. A total of 58 differentially represented protein species were identified in artificially inoculated leaves. Although the pathogen increased its population density during the initial period of apoplast colonization, plant defense mechanisms were able to impede further disease development. We identified a concerted action of different proteins mainly belonging to the plant defense and metabolism category, which intervened at different times and participated in reducing the pathogen population. On the other hand, bacterial BamA was highly represented during the first week of leaf apoplast colonization, whereas OmpA and Cpn60 were induced later. In addition to presenting further proteomic information on the molecular factors actively participating in this pathosystem, our data characterize the early events of host colonization and will promote the eventual development of novel bioassays for pathogen detection in kiwiplants. Biological significance This original study evaluates on a proteomic perspective the interaction occurring into the leaf apoplast between Actinidia deliciosa and its specific pathogen Pseudomonas syringae pv. Actinidiae. Despite the initial bacterial multiplication, a concerted action of the plant defense mechanisms blocked the infection during 21 days of apoplast colonization, as revealed by the number of differentially-represented proteins identified in artificially-inoculated and control leaves. Three bacterial proteins were also recognized among the over-represented molecules in infected plants. This study may contribute to improve breeding programs aimed at selecting resistant/tolerant kiwifruit cultivars toward P. syringae pv. Actinidiae, which present a high representation of the plant proteins here shown to be involved in resistance mechanisms. In addition to present additional information on the molecular players actively participating in this pathosystem, our data will also facilitate the technological development of future bioassays for the detection of this pathogen in kiwiplants.
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proteomic changes in Actinidia chinensis shoot during systemic infection with a pandemic pseudomonas syringae pv Actinidiae strain
Journal of Proteomics, 2013Co-Authors: Milena Petriccione, Ilaria Di Cecco, Andrea Scaloni, Simona Arena, M ScortichiniAbstract:A pandemic, very aggressive population of Pseudomonas syringae pv. Actinidiae is currently causing severe economic losses to kiwifruit crops worldwide. Upon leaf attack, this Gram-negative bacterium systemically reaches the plant shoot in a week period. In this study, combined 2-DE and nanoLC-ESI-LIT-MS/MS procedures were used to describe major proteomic changes in Actinidia chinensis shoot following bacterial inoculation in host leaf. A total of 117 differentially represented protein spots were identified in infected and control shoots. Protein species associated with plant defence, including type-members of the plant basal defence, pathogenesis, oxidative stress and heat shock, or with transport and signalling events, were the most represented category of induced components. Proteins involved in carbohydrate metabolism and photosynthesis were also augmented upon infection. In parallel, a bacterial outer membrane polypeptide component was identified in shoot tissues, whose homologues were already linked to bacterial virulence in other eukaryotes. Semiquantitative RT-PCR analysis confirmed expression data for all selected plant gene products. All these data suggest a general reprogramming of shoot metabolism following pathogen systemic infection, highlighting organ-specific differences within the context of a general similarity with respect to other pathosystems. In addition to present preliminary information on the molecular mechanisms regulating this specific plant-microbe interaction, our results will foster future proteomic studies aimed at characterizing the very early events of host colonization, thus promoting the development of novel bioassays for pathogen detection in kiwifruit material.
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pseudomonas syringae pv Actinidiae draft genomes comparison reveal strain specific features involved in adaptation and virulence to Actinidia species
PLOS ONE, 2011Co-Authors: Simone Marcelletti, Milena Petriccione, Patrizia Ferrante, Giuseppe Firrao, M ScortichiniAbstract:A recent re-emerging bacterial canker disease incited by Pseudomonas syringae pv. Actinidiae (Psa) is causing severe economic losses to Actinidia chinensis and A. deliciosa cultivations in southern Europe, New Zealand, Chile and South Korea. Little is known about the genetic features of this pathovar. We generated genome-wide Illumina sequence data from two Psa strains causing outbreaks of bacterial canker on the A. deliciosa cv. Hayward in Japan (J-Psa, type-strain of the pathovar) and in Italy (I-Psa) in 1984 and 1992, respectively as well as from a Psa strain (I2-Psa) isolated at the beginning of the recent epidemic on A. chinensis cv. Hort16A in Italy. All strains were isolated from typical leaf spot symptoms. The phylogenetic relationships revealed that Psa is more closely related to P. s. pv. theae than to P. avellanae within genomospecies 8. Comparative genomic analyses revealed both relevant intrapathovar variations and putative pathovar-specific genomic regions in Psa. The genomic sequences of J-Psa and I-Psa were very similar. Conversely, the I2-Psa genome encodes four additional effector protein genes, lacks a 50 kb plasmid and the phaseolotoxin gene cluster, argK-tox but has acquired a 160 kb plasmid and putative prophage sequences. Several lines of evidence from the analysis of the genome sequences support the hypothesis that this strain did not evolve from the Psa population that caused the epidemics in 1984–1992 in Japan and Italy but rather is the product of a recent independent evolution of the pathovar Actinidiae for infecting Actinidia spp. All Psa strains share the genetic potential for copper resistance, antibiotic detoxification, high affinity iron acquisition and detoxification of nitric oxide of plant origin. Similar to other sequenced phytopathogenic pseudomonads associated with woody plant species, the Psa strains isolated from leaves also display a set of genes involved in the catabolism of plant-derived aromatic compounds.
Michael J Boland - One of the best experts on this subject based on the ideXlab platform.
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dietary actinidin from kiwifruit Actinidia deliciosa cv hayward increases gastric digestion and the gastric emptying rate of several dietary proteins in growing rats
Journal of Nutrition, 2014Co-Authors: Carlos A Montoya, Jason P Hindmarsh, Lucrecia Gonzalez, Michael J Boland, Paul J Moughan, Shane M RutherfurdAbstract:Dietary actinidin influences the extent to which some dietary proteins are digested in the stomach, and it is hypothesized that the latter modulation will in turn affect their gastric emptying rate (GE). In this study, the effect of dietary actinidin on GE and gastric digestion of 6 dietary protein sources was determined in growing rats. Each dietary protein source [beef muscle, gelatin, gluten, soy protein isolate (SPI), whey protein isolate, and zein] was included in 2 semisynthetic diets as the sole nitrogensource. For each protein source, 1 of the 2 diets contained actinidin [76.5 U/g dry matter (DM)] in the form of ground freeze-dried green kiwifruit (Actinidia deliciosa cv. Hayward), whereas the other diet contained freeze-dried gold kiwifruit (Actinidia chinensis cv. Hort16A), which is devoid of actinidin (3.4 U/g DM). For both diets, dietary kiwifruit represented 20% of the diet on a DM basis. The real-time GE was determined in rats gavaged with a single dose of the diets using magnetic resonance spectroscopy over 150 min (n = 8 per diet). Gastric protein digestion was determined based on the free amino groups in the stomach chyme collected from rats fed the diets (n = 8 per diet) that were later killed. GE differed across the protein sources [e.g., the half gastric emptying time (TΩ) ranged from 157 min for gluten to 266 min for zein] (P < 0.05). Dietary actinidin increased the gastric digestion of beef muscle (0.6-fold), gluten (3.2-fold), and SPI (0.6-fold) and increased the GE of the diets containing beef muscle (43% TΩ) and zein (23% TΩ; P < 0.05). There was an inverse correlation between gastric protein digestion and DM retained in the stomach (r = 20.67; P < 0.05). In conclusion, dietary actinidin increased gastric protein digestion and accelerated the GE for several dietary protein sources. GE may be influenced by gastric protein digestion, and dietary actinidin can be used to modulate GE and protein digestion in the stomach of some dietary protein sources but not others. J. Nutr. 144: 440‐446, 2014.
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actinidin from kiwifruit Actinidia deliciosa cv hayward increases the digestion and rate of gastric emptying of meat proteins in the growing pig
British Journal of Nutrition, 2014Co-Authors: Carlos A Montoya, Michael J Boland, Shane M Rutherfurd, Trent D Olson, Ajitpal S Purba, Lynley Drummond, Paul J MoughanAbstract:The present study aimed to investigate the effect of dietary actinidin on the kinetics of gastric digestion of beef muscle proteins and on the rate of stomach emptying in growing pigs. For this purpose, 120 pigs (mean body weight 28 ( sd 2·9) kg) were fed beef muscle protein-based diets containing either actinidin (fresh green kiwifruit pulp or gold kiwifruit pulp supplemented with purified actinidin) or no actinidin (fresh gold kiwifruit pulp or green kiwifruit pulp with inactivated actinidin). Additionally, fifteen pigs were fed with a protein-free diet to determine the endogenous protein flow. Pigs were euthanised at exactly 0·5, 1, 3, 5 and 7 h postprandially ( n 6 per time point for each kiwifruit diet and n 3 for protein-free diet). Stomach chyme was collected for measuring gastric retention, actinidin activity, individual beef muscle protein digestion based on SDS–PAGE and the degree of hydrolysis based on the appearance of free amino groups. The stomach emptying of DM and N was faster when actinidin was present in the diet ( P v . 172 min ( ± 7·4 min pooled standard error) for the diets with and without actinidin, respectively. The presence of dietary actinidin in the stomach chyme increased the digestion of beef muscle protein ( P 34 kDa; P
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effect of actinidin from kiwifruit Actinidia deliciosa cv hayward on the digestion of food proteins determined in the growing rat
Food Chemistry, 2011Co-Authors: Shane M Rutherfurd, Carlos A Montoya, Paul J Moughan, Lynley Drummond, Michael J BolandAbstract:Abstract This study aimed to determine the effect of dietary actinidin (provided as Hayward kiwifruit) on the gastric and small intestine digestion of six food protein sources in rats. For each protein source, two semi-synthetic test diets were formulated containing either freeze-dried Hayward kiwifruit (actinidin present) or freeze-dried Hort16A kiwifruit (actinidin absent). Actinidin activity is extremely low in Hort16A kiwifruit. Titanium dioxide was also included as an indigestible marker. Rats were fed freshly-prepared diets, euthanised and the gastric and ileal contents collected. The chyme and digesta samples were subjected to electrophoresis (SDS–PAGE), densitometry and titanium analysis and the degradability of individual proteins calculated. Dietary actinidin had no ( p > 0.05) effect on the gastric degradability of zein and whey protein isolate but increased gastric degradability of beef muscle protein, gelatin, soy protein isolate and gluten by 40%, 60%, 27% and 29% units, respectively. Dietary actinidin had little or no effect on ileal protein degradability. Overall, dietary actinidin enhanced the gastric digestion of some food proteins.
