The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Russell L Jones - One of the best experts on this subject based on the ideXlab platform.
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the arabidopsis Aleurone layer responds to nitric oxide gibberellin and abscisic acid and is sufficient and necessary for seed dormancy
Plant Physiology, 2007Co-Authors: Paul C Bethke, Igor G L Libourel, Natsuyo Aoyaman Aoyama, Yongyoon Chung, David W Still, Russell L JonesAbstract:Seed dormancy is a common phase of the plant life cycle, and several parts of the seed can contribute to dormancy. Whole seeds, seeds lacking the testa, embryos, and isolated Aleurone layers of Arabidopsis (Arabidopsis thaliana) were used in experiments designed to identify components of the Arabidopsis seed that contribute to seed dormancy and to learn more about how dormancy and germination are regulated in this species. The Aleurone layer was found to be the primary determinant of seed dormancy. Embryos from dormant seeds, however, had a lesser growth potential than those from nondormant seeds. Arabidopsis Aleurone cells were examined by light and electron microscopy, and cell ultrastructure was similar to that of cereal Aleurone cells. Arabidopsis Aleurone cells responded to nitric oxide (NO), gibberellin (GA), and abscisic acid, with NO being upstream of GA in a signaling pathway that leads to vacuolation of protein storage vacuoles and abscisic acid inhibiting vacuolation. Molecular changes that occurred in embryos and Aleurone layers prior to germination were measured, and these data show that both the Aleurone layer and the embryo expressed the NO-associated gene AtNOS1, but only the embryo expressed genes for the GA biosynthetic enzyme GA3 oxidase.
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cprg hcl a potential h cl symporter prevents acidification of storage vacuoles in Aleurone cells and inhibits ga dependent hydrolysis of storage protein and phytate
Plant Journal, 2003Co-Authors: Yong-sic Hwang, Paul C Bethke, Frank Gubler, Russell L JonesAbstract:Summary The putative H+/Cl− symporter cycloprodigiosin-HCl (cPrG-HCl) was used to investigate the role of vacuole acidification in cereal Aleurone cell function. The protein storage vacuole (PSV) becomes acidified rapidly when Aleurone cells are treated with gibberellic acid (GA) but not abscisic acid (ABA). We show that cPrG prevents PSV acidification in Aleurone layers and prevents synthesis of secretory proteins such as α-amylase. Our data support the hypothesis that decreased hydrolase synthesis is a consequence of decreased hydrolysis of storage proteins in PSV. Support for this hypothesis comes from experiments showing that breakdown of barley 7S globulins and phytate is inhibited by cPrG in GA-treated Aleurone layers. Decreased mobilization of PSV reserves is accompanied by reductions in the free amino acid pool size and in the amount of ions released from the Aleurone layer. Vacuolation of the Aleurone cell is a diagnostic feature of the response to GA, and vacuolation is also inhibited by cPrG. Evidence that cPrG acts as a potential H+/Cl− symporter in Aleurone is presented. We show that cPrG does not inhibit the synthesis and secretion of α-amylase when Cl− ions are omitted from the incubation medium. Although cPrG blocks many GA-induced responses of Aleurone layers, it does not affect early steps in GA signaling. The SLN1 protein, a negative regulator of GA signaling, is turned over in GA-treated cells in the presence and absence of cPrG. Similarly, synthesis of the transcriptional activator GAMYB is unaffected by the presence of cPrG in GA-treated cells.
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cPrG-HCl a potential H+/Cl- symporter prevents acidification of storage vacuoles in Aleurone cells and inhibits GA-dependent hydrolysis of storage protein and phytate.
The Plant journal : for cell and molecular biology, 2003Co-Authors: Yong-sic Hwang, Paul C Bethke, Frank Gubler, Russell L JonesAbstract:Summary The putative H+/Cl− symporter cycloprodigiosin-HCl (cPrG-HCl) was used to investigate the role of vacuole acidification in cereal Aleurone cell function. The protein storage vacuole (PSV) becomes acidified rapidly when Aleurone cells are treated with gibberellic acid (GA) but not abscisic acid (ABA). We show that cPrG prevents PSV acidification in Aleurone layers and prevents synthesis of secretory proteins such as α-amylase. Our data support the hypothesis that decreased hydrolase synthesis is a consequence of decreased hydrolysis of storage proteins in PSV. Support for this hypothesis comes from experiments showing that breakdown of barley 7S globulins and phytate is inhibited by cPrG in GA-treated Aleurone layers. Decreased mobilization of PSV reserves is accompanied by reductions in the free amino acid pool size and in the amount of ions released from the Aleurone layer. Vacuolation of the Aleurone cell is a diagnostic feature of the response to GA, and vacuolation is also inhibited by cPrG. Evidence that cPrG acts as a potential H+/Cl− symporter in Aleurone is presented. We show that cPrG does not inhibit the synthesis and secretion of α-amylase when Cl− ions are omitted from the incubation medium. Although cPrG blocks many GA-induced responses of Aleurone layers, it does not affect early steps in GA signaling. The SLN1 protein, a negative regulator of GA signaling, is turned over in GA-treated cells in the presence and absence of cPrG. Similarly, synthesis of the transcriptional activator GAMYB is unaffected by the presence of cPrG in GA-treated cells.
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Active oxygen and cell death in cereal Aleurone cells.
Journal of experimental botany, 2002Co-Authors: Angelika Fath, Paul C Bethke, Veronica Beligni, Russell L JonesAbstract:The cereal Aleurone layer is a secretory tissue whose function is regulated by gibberellic acid (GA) and abscisic acid (ABA). Aleurone cells lack functional chloroplasts, thus excluding photosynthesis as a source of active oxygen species (AOS) in cell death. Incubation of barley Aleurone layers or protoplasts in GA initiated the cell death programme, but incubation in ABA delays programmed cell death (PCD). Light, especially blue and UV-A light, and H 2 O 2 accelerate PCD of GA-treated Aleurone cells, but ABA-treated Aleurone cells are refractory to light and H 2 O 2 and are not killed. It was shown that light elevated intracellular H 2 O 2 , and that the rise in H 2 O 2 was greater in GA-treated cells compared to cells in ABA. Experiments with antioxidants show that PCD in Aleurone is probably regulated by AOS. The sensitivity of GA-treated Aleurone to light and H 2 O 2 is a result of lowered amounts of enzymes that metabolize AOS. mRNAs encoding catalase, ascorbate peroxidase and superoxide dismutase are all reduced during 6-18 h of incubation in GA, but these mRNAs were present in higher amounts in cells incubated in ABA. The amounts of protein and enzyme activities encoded by these mRNAs were also dramatically reduced in GA-treated cells. Aleurone cells store and metabolize neutral lipids via the glyoxylate cycle in response to GA, and glyoxysomes are one potential source of AOS in the GA-treated cells. Mitochondria are another potential source of AOS in GA-treated cells. AOS generated by these organelles bring about membrane rupture and cell death.
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Signalling in the cereal Aleurone: hormones, reactive oxygen and cell death
New Phytologist, 2001Co-Authors: Angelika Fath, Paul C Bethke, Maria V. Belligni, Yoav N. Spiegel, Russell L JonesAbstract:ummary The cereal Aleurone is widely used as a model system to study hormonal signalling. Abscisic acid (ABA) and gibberellins (GAs) elicit distinct responses in Aleurone cells, ranging from those occurring within minutes of hormone addition to those that require several hours or days to complete. Programmed cell death is an example of a response in Aleurone layers that is hormonally regulated. GAs promote cell death and cells in intact Aleurone layers begin to die 24 h after GA treatment, whereas cell death of Aleurone protoplasts begins 4 d after GA treatment. ABA prevents Aleurone cell death and addition of ABA to cells pretreated with GA can delay cell death. Aleurone cells do not follow the apoptotic route of programmed cell death. Cells treated with GA, but not ABA, develop large, acidic vacuoles containing a spectrum of hydrolases typical of lytic compartments. Enzymes that metabolize reactive oxygen species are also present in Aleurone cells, but ascorbate peroxidase, catalase and superoxide dismutase become less abundant after treatment with GA; activity of these enzymes increases or remains unchanged in ABA-treated cells. We propose a model whereby reactive oxygen species accumulate in GA-treated cells and lead to peroxidation of membrane lipids and plasma membrane rupture. Abbreviations RO, reactive oxygen species; HR, hypersensitive response; PSV, protein storage vacuole; PCD, programmed cell death; CAT, catalase; SOD, superoxide dismutase; APX, ascorbate peroxidase.
Paul C Bethke - One of the best experts on this subject based on the ideXlab platform.
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the arabidopsis Aleurone layer responds to nitric oxide gibberellin and abscisic acid and is sufficient and necessary for seed dormancy
Plant Physiology, 2007Co-Authors: Paul C Bethke, Igor G L Libourel, Natsuyo Aoyaman Aoyama, Yongyoon Chung, David W Still, Russell L JonesAbstract:Seed dormancy is a common phase of the plant life cycle, and several parts of the seed can contribute to dormancy. Whole seeds, seeds lacking the testa, embryos, and isolated Aleurone layers of Arabidopsis (Arabidopsis thaliana) were used in experiments designed to identify components of the Arabidopsis seed that contribute to seed dormancy and to learn more about how dormancy and germination are regulated in this species. The Aleurone layer was found to be the primary determinant of seed dormancy. Embryos from dormant seeds, however, had a lesser growth potential than those from nondormant seeds. Arabidopsis Aleurone cells were examined by light and electron microscopy, and cell ultrastructure was similar to that of cereal Aleurone cells. Arabidopsis Aleurone cells responded to nitric oxide (NO), gibberellin (GA), and abscisic acid, with NO being upstream of GA in a signaling pathway that leads to vacuolation of protein storage vacuoles and abscisic acid inhibiting vacuolation. Molecular changes that occurred in embryos and Aleurone layers prior to germination were measured, and these data show that both the Aleurone layer and the embryo expressed the NO-associated gene AtNOS1, but only the embryo expressed genes for the GA biosynthetic enzyme GA3 oxidase.
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cprg hcl a potential h cl symporter prevents acidification of storage vacuoles in Aleurone cells and inhibits ga dependent hydrolysis of storage protein and phytate
Plant Journal, 2003Co-Authors: Yong-sic Hwang, Paul C Bethke, Frank Gubler, Russell L JonesAbstract:Summary The putative H+/Cl− symporter cycloprodigiosin-HCl (cPrG-HCl) was used to investigate the role of vacuole acidification in cereal Aleurone cell function. The protein storage vacuole (PSV) becomes acidified rapidly when Aleurone cells are treated with gibberellic acid (GA) but not abscisic acid (ABA). We show that cPrG prevents PSV acidification in Aleurone layers and prevents synthesis of secretory proteins such as α-amylase. Our data support the hypothesis that decreased hydrolase synthesis is a consequence of decreased hydrolysis of storage proteins in PSV. Support for this hypothesis comes from experiments showing that breakdown of barley 7S globulins and phytate is inhibited by cPrG in GA-treated Aleurone layers. Decreased mobilization of PSV reserves is accompanied by reductions in the free amino acid pool size and in the amount of ions released from the Aleurone layer. Vacuolation of the Aleurone cell is a diagnostic feature of the response to GA, and vacuolation is also inhibited by cPrG. Evidence that cPrG acts as a potential H+/Cl− symporter in Aleurone is presented. We show that cPrG does not inhibit the synthesis and secretion of α-amylase when Cl− ions are omitted from the incubation medium. Although cPrG blocks many GA-induced responses of Aleurone layers, it does not affect early steps in GA signaling. The SLN1 protein, a negative regulator of GA signaling, is turned over in GA-treated cells in the presence and absence of cPrG. Similarly, synthesis of the transcriptional activator GAMYB is unaffected by the presence of cPrG in GA-treated cells.
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cPrG-HCl a potential H+/Cl- symporter prevents acidification of storage vacuoles in Aleurone cells and inhibits GA-dependent hydrolysis of storage protein and phytate.
The Plant journal : for cell and molecular biology, 2003Co-Authors: Yong-sic Hwang, Paul C Bethke, Frank Gubler, Russell L JonesAbstract:Summary The putative H+/Cl− symporter cycloprodigiosin-HCl (cPrG-HCl) was used to investigate the role of vacuole acidification in cereal Aleurone cell function. The protein storage vacuole (PSV) becomes acidified rapidly when Aleurone cells are treated with gibberellic acid (GA) but not abscisic acid (ABA). We show that cPrG prevents PSV acidification in Aleurone layers and prevents synthesis of secretory proteins such as α-amylase. Our data support the hypothesis that decreased hydrolase synthesis is a consequence of decreased hydrolysis of storage proteins in PSV. Support for this hypothesis comes from experiments showing that breakdown of barley 7S globulins and phytate is inhibited by cPrG in GA-treated Aleurone layers. Decreased mobilization of PSV reserves is accompanied by reductions in the free amino acid pool size and in the amount of ions released from the Aleurone layer. Vacuolation of the Aleurone cell is a diagnostic feature of the response to GA, and vacuolation is also inhibited by cPrG. Evidence that cPrG acts as a potential H+/Cl− symporter in Aleurone is presented. We show that cPrG does not inhibit the synthesis and secretion of α-amylase when Cl− ions are omitted from the incubation medium. Although cPrG blocks many GA-induced responses of Aleurone layers, it does not affect early steps in GA signaling. The SLN1 protein, a negative regulator of GA signaling, is turned over in GA-treated cells in the presence and absence of cPrG. Similarly, synthesis of the transcriptional activator GAMYB is unaffected by the presence of cPrG in GA-treated cells.
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Active oxygen and cell death in cereal Aleurone cells.
Journal of experimental botany, 2002Co-Authors: Angelika Fath, Paul C Bethke, Veronica Beligni, Russell L JonesAbstract:The cereal Aleurone layer is a secretory tissue whose function is regulated by gibberellic acid (GA) and abscisic acid (ABA). Aleurone cells lack functional chloroplasts, thus excluding photosynthesis as a source of active oxygen species (AOS) in cell death. Incubation of barley Aleurone layers or protoplasts in GA initiated the cell death programme, but incubation in ABA delays programmed cell death (PCD). Light, especially blue and UV-A light, and H 2 O 2 accelerate PCD of GA-treated Aleurone cells, but ABA-treated Aleurone cells are refractory to light and H 2 O 2 and are not killed. It was shown that light elevated intracellular H 2 O 2 , and that the rise in H 2 O 2 was greater in GA-treated cells compared to cells in ABA. Experiments with antioxidants show that PCD in Aleurone is probably regulated by AOS. The sensitivity of GA-treated Aleurone to light and H 2 O 2 is a result of lowered amounts of enzymes that metabolize AOS. mRNAs encoding catalase, ascorbate peroxidase and superoxide dismutase are all reduced during 6-18 h of incubation in GA, but these mRNAs were present in higher amounts in cells incubated in ABA. The amounts of protein and enzyme activities encoded by these mRNAs were also dramatically reduced in GA-treated cells. Aleurone cells store and metabolize neutral lipids via the glyoxylate cycle in response to GA, and glyoxysomes are one potential source of AOS in the GA-treated cells. Mitochondria are another potential source of AOS in GA-treated cells. AOS generated by these organelles bring about membrane rupture and cell death.
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Signalling in the cereal Aleurone: hormones, reactive oxygen and cell death
New Phytologist, 2001Co-Authors: Angelika Fath, Paul C Bethke, Maria V. Belligni, Yoav N. Spiegel, Russell L JonesAbstract:ummary The cereal Aleurone is widely used as a model system to study hormonal signalling. Abscisic acid (ABA) and gibberellins (GAs) elicit distinct responses in Aleurone cells, ranging from those occurring within minutes of hormone addition to those that require several hours or days to complete. Programmed cell death is an example of a response in Aleurone layers that is hormonally regulated. GAs promote cell death and cells in intact Aleurone layers begin to die 24 h after GA treatment, whereas cell death of Aleurone protoplasts begins 4 d after GA treatment. ABA prevents Aleurone cell death and addition of ABA to cells pretreated with GA can delay cell death. Aleurone cells do not follow the apoptotic route of programmed cell death. Cells treated with GA, but not ABA, develop large, acidic vacuoles containing a spectrum of hydrolases typical of lytic compartments. Enzymes that metabolize reactive oxygen species are also present in Aleurone cells, but ascorbate peroxidase, catalase and superoxide dismutase become less abundant after treatment with GA; activity of these enzymes increases or remains unchanged in ABA-treated cells. We propose a model whereby reactive oxygen species accumulate in GA-treated cells and lead to peroxidation of membrane lipids and plasma membrane rupture. Abbreviations RO, reactive oxygen species; HR, hypersensitive response; PSV, protein storage vacuole; PCD, programmed cell death; CAT, catalase; SOD, superoxide dismutase; APX, ascorbate peroxidase.
Valérie Micard - One of the best experts on this subject based on the ideXlab platform.
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Disintegration of wheat Aleurone structure has an impact on the bioavailability of phenolic compounds and other phytochemicals as evidenced by altered urinary metabolite profile of diet-induced obese mice
Nutrition & Metabolism, 2014Co-Authors: Jenna Pekkinen, Natalia N Rosa, Otto-ilari Savolainen, Hannu Mykkänen, Valérie Micard, Pekka Keski-rahkonen, Kati HanhinevaAbstract:Background Phenolic acids are covalently bound to the arabinoxylan fibre matrix of wheat Aleurone layer. In order to be bioavailable they need to be released by endogenous or bacterial enzymes and absorbed within the intestinal lumen. The intestinal microbiota can metabolize phenolic acids and other food-born phytochemicals. However, the effect of structure of the cereal bran or Aleurone layer on these processes is not comprehensively studied. Methods The structure of Aleurone layer was modified either by dry-grinding or by enzymatic treatments with xylanase alone or in combination with feruloyl esterase. Diet induced obese C57BL6/J mice were fed with high-fat diets containing either pure ferulic acid, or one of the four differentially treated Aleurone preparations for 8 weeks. The diets were designed to be isocaloric and to have similar macronutrient composition. The urinary metabolite profiles were investigated using non-targeted LC-qTOF-MS-metabolomics approach. Results The different dietary groups were clearly separated in the principal component analysis. Enzymatic processing of Aleurone caused increased excretion of ferulic acid sulfate and glycine conjugates reflecting the increase in unbound form of readily soluble ferulic acid in the diet. The urinary metabolite profile of the diet groups containing native and cryo-ground Aleurone was more intense with metabolites derived from microbial processing including hippuric acid, hydroxyl- and dihydroxyphenylpropionic acids. Furthermore, Aleurone induced specific fingerprint on the urinary metabolite profile seen as excretion of benzoxazinoid metabolites, several small dicarboyxlic acids, and various small nitrogen containing compounds. Conclusions The structural modifications on wheat Aleurone fraction resulted in altered metabolism of Aleurone derived phenolic acids and other phytochemicals excreted in urine of diet-induced obese mice.
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effects of disintegration on in vitro fermentation and conversion patterns of wheat Aleurone in a metabolical colon model
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Natalia N Rosa, Annamarja Aura, Luc Saulnier, Ulla Holopainenmantila, Kaisa Poutanen, Valérie MicardAbstract:This work aimed to elucidate the effect of wheat Aleurone integrity on its fermentability, i.e., the formation of short-chain fatty acids (SCFA) and microbial phenolic metabolites, in an in vitro model using human faecal microbiota as an inoculum. The structure of Aleurone was modified by mechanical (dry grinding) or enzymatic (xylanase with or without feruloyl esterase) treatments in order to increase its physical accessibility and degrade its complex cell-wall network. The ground Aleurone (smaller particle size) produced slightly more SCFA than the native Aleurone during the first 8 h but a similar amount at 24 h (102.5 and 101 mmol/L, respectively). Similar colonic metabolism of ferulic acid (FA) was observed for native and ground Aleurone. The enzymatic treatments of Aleurone allowed a high solubilization of arabinoxylan (up to 82%) and a high release of FA in its conjugated and free forms (up to 87%). The enzymatic disintegration of Aleurone's structure led to a higher concentration and formation rate of the colonic metabolites of FA (especially phenylpropionic acids) but did not change significantly the formation of SCFA (81 mmol/L for enzyme treated versus 101 mmol/L for the native Aleurone).
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Exposure or release of ferulic acid from wheat Aleurone: Impact on its antioxidant capacity
Food Chemistry, 2013Co-Authors: Natalia Rosa, Valerie Lullien-pellerin, Claire Dufour, Valérie MicardAbstract:The relationship between the Aleurone cell integrity and the exposure or release of bioavailable ferulic acid (FA) with the antioxidant capacity of Aleurone in in vitro and under simulated gastric conditions was explored. The antioxidant capacity of Aleurone was increased by around 2-fold when its median particle size was reduced to under 50µm. The opening of Aleurone cells increased the physical exposure of FA bound to the insoluble polysaccharides, which seemed to be responsible of the increased antioxidant capacity. Synergistic combination of xylanase and feruloyl esterase was found to be the most efficient enzymatic treatment releasing up to 86% of total FA in bioaccessible forms. This enzymatic treatment significantly enhanced the radical scavenging activity of Aleurone by up to 4-fold, which overlapped the overall antioxidant potential estimated from the total content of FA in Aleurone.The improvement in the antioxidant capacity of Aleurone was also observed in the simulated gastric digestion by inhibition of lipid oxidation.
Azar Shahpiri - One of the best experts on this subject based on the ideXlab platform.
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ethephon advances the release time of limit dextrinase from gibberellic acid treated Aleurone layer
Biocatalysis and agricultural biotechnology, 2017Co-Authors: Samaneh Siapush, Azar ShahpiriAbstract:Abstract The Aleurone layer plays a key role in germination by responding to hormone signals from embryo and producing hydrolases. The barley Aleurone layer can be separated from the other seed tissues and maintained in culture, allowing the study of the effect of added signaling molecules in an isolated system. In this work, the effect of ethephon on the protein release from gibberellic acid (GA)-treated Aleurone layer was presented for two important enzymes in starch degradation: α-amylase and limit dextrinase (LD). The results showed that the release of proteins from Aleurone layer to culture supernatant was remarkably increased when GA- treated Aleurone layer was exposed to 1000–10000 ppm ethephon. Ethephon enhanced the release of α-amylase and advanced the release time of LD from GA-treated Aleurone layer to culture supernatant. The results supports that the release of LD is dependent to cell wall degradation which can be induced by the effect of ethephon.
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spatio temporal appearance of α amylase and limit dextrinase in barley Aleurone layer in response to gibberellic acid abscisic acid and salicylic acid
Journal of the Science of Food and Agriculture, 2015Co-Authors: Azar Shahpiri, Nasim Talaei, Christine FinnieAbstract:BACKGROUND Cereal seed germination involves mobilization of storage reserves in the starchy endosperm to support seedling growth. In response to gibberellin produced by the embryo the Aleurone layer synthesizes hydrolases that are secreted to the endosperm for degradation of storage products. In this study analysis of intracellular protein accumulation and release from barley Aleurone layers is presented for the important enzymes in starch degradation: α-amylase and limit dextrinase (LD). RESULTS Proteins were visualized by immunoblotting in Aleurone layers and culture supernatants from dissected Aleurone layers incubated up to 72 h with either gibberellic acid (GA), abscisic acid (ABA) or salicylic acid (SA). The results show that α-amylase is secreted from Aleurone layer treated with GA soon after synthesis but the release of LD to culture supernatants was significantly delayed and coincided with a general loss of proteins from Aleurone layers. CONCLUSIONS Release of LD was found to differ from that of amylase and was suggested to depend on programmed cell death (PCD). Despite detection of intracellular amylase in untreated Aleurone layers or Aleurone layers treated with ABA or SA, α-amylase was not released from these samples. Nevertheless, the release of α-amylase was observed from Aleurone layers treated with GA+ABA or GA+SA. © 2014 Society of Chemical Industry
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Spatio‐temporal appearance of α‐amylase and limit dextrinase in barley Aleurone layer in response to gibberellic acid, abscisic acid and salicylic acid
Journal of the Science of Food and Agriculture, 2014Co-Authors: Azar Shahpiri, Nasim Talaei, Christine FinnieAbstract:BACKGROUND Cereal seed germination involves mobilization of storage reserves in the starchy endosperm to support seedling growth. In response to gibberellin produced by the embryo the Aleurone layer synthesizes hydrolases that are secreted to the endosperm for degradation of storage products. In this study analysis of intracellular protein accumulation and release from barley Aleurone layers is presented for the important enzymes in starch degradation: α-amylase and limit dextrinase (LD). RESULTS Proteins were visualized by immunoblotting in Aleurone layers and culture supernatants from dissected Aleurone layers incubated up to 72 h with either gibberellic acid (GA), abscisic acid (ABA) or salicylic acid (SA). The results show that α-amylase is secreted from Aleurone layer treated with GA soon after synthesis but the release of LD to culture supernatants was significantly delayed and coincided with a general loss of proteins from Aleurone layers. CONCLUSIONS Release of LD was found to differ from that of amylase and was suggested to depend on programmed cell death (PCD). Despite detection of intracellular amylase in untreated Aleurone layers or Aleurone layers treated with ABA or SA, α-amylase was not released from these samples. Nevertheless, the release of α-amylase was observed from Aleurone layers treated with GA+ABA or GA+SA. © 2014 Society of Chemical Industry
Roger M. Spanswick - One of the best experts on this subject based on the ideXlab platform.
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Isolation of ripening rice (Oryza sativa L.) Aleurone protoplasts for uptake studies
Plant Science, 2007Co-Authors: Jordan O. Hay, Roger M. SpanswickAbstract:The Aleurone layer of the developing rice (Oryza sativa L.) caryopsis is the first filial tissue in a position to take up sucrose released into the endosperm apoplast by the maternal nucellus. Adhesion of the Aleurone layer to the nucellus during ripening makes it difficult to characterize sucrose transport by the Aleurone layer. As an alternative, Aleurone protoplasts were isolated enzymatically in a two-step process in which the cells were released from the caryopsis before the protoplasts were isolated. The procedure prevented the formation of maternal and giant (fused) Aleurone protoplasts. Low protoplast yield (10% of the number of cells) was correlated with the low viability of the isolated cells. To test the utility of the protoplast system, sucrose uptake by the protoplasts was investigated using the silicone oil centrifugation technique. The concentration-dependence of the influx was biphasic and could be fitted by a function that depended on three parameters to describe the saturable and non-saturable components of the influx. These results demonstrate that it is possible to isolate protoplasts rapidly from the Aleurone layer in high enough yield for protoplast uptake studies and are consistent with the Aleurone layer having a saturable and a non-saturable component of sucrose influx.