scholarly journals Measurement of the Concentration of Bioactive Gibberellin in Germinating Rice Seed Using the .ALPHA.-Amylase Induction from Aleurone Cells

2005 ◽  
Vol 52 (4) ◽  
pp. 399-402
Author(s):  
Shin-ichiro Mitsunaga ◽  
Osamu Kawakami ◽  
Junji Yamaguchi ◽  
Toshiaki Mitsui
Keyword(s):  
Alpha Amylase ◽  
Rice Seed ◽  
Aleurone Cells ◽  
Amylase Induction

scholarly journals Action of gibberellic acid (GA3) on dormancy and activity of alpha-amylase in rice seeds

2002 ◽  
Vol 24 (2) ◽  
pp. 43-48 ◽  
Author(s):  
Antônio Rodrigues Vieira ◽  
Maria das Graças Guimarães Carvalho Vieira ◽  
Antônio C. Fraga ◽  
João Almir Oliveira ◽  
Custódio D. dos Santos
Keyword(s):  
Enzyme Activity ◽  
Gibberellic Acid ◽  
Seed Dormancy ◽  
Amylase Activity ◽  
Alpha Amylase ◽  
Rice Seed ◽  
Efficient Treatment ◽  
Soaking Time ◽  
Forced Air ◽  
Air Circulation

To evaluate the effectiveness of gibberellic acid (GA3) in breaking rice seed dormancy and the use of alpha-amylase enzyme activity as an indicator of the dormancy level, seed from the intensively dormant irrigated cultivar Urucuia were used. The seeds were submitted to a pre-drying process in a forced air circulation chamber under 40ºC during 7 days and submersed in 30 mL of GA3 solution under 0, 10, 30 and 60 mg/L H2O concentrations, during 2, 24 and 36 hours. After the treatments, the alpha-amylase activity was determined by using the polyacrilamide electrophoresis and spectrophotometry. At the same time, the germination test was made. The results indicated a gain in germination and in alpha-amylase activity in higher concentrations and soaking time of seeds in GA3. These observations support the conclusion that soaking seed in 60 mg GA3/L during 36 hours can be used as a quick and efficient treatment in breaking rice seed dormancy and is equivalent to the forced air circulation chamber at 40ºC during 7 days. The alpha-amylase enzyme activity proved to be as an efficient marker of the seeds dormancy level.

scholarly journals Biosynthesis of rice seed alpha-amylase: proteolytic processing and glycosylation of precursor polypeptides by microsomes.

1983 ◽  
Vol 96 (3) ◽  
pp. 802-806 ◽  
Author(s):  
S Miyata ◽  
T Akazawa
Keyword(s):  
Signal Sequence ◽  
Inhibitory Effect ◽  
Secretory Protein ◽  
Proteolytic Processing ◽  
Alpha Amylase ◽  
Rice Seed ◽  
Microsomal Membranes ◽  
Enzyme Molecules ◽  
Triton X ◽  
Polypeptide Chains

Microsomes prepared from the rice seed scutellum were incubated in wheat germ extracts (S-100 fraction) to direct the synthesis of alpha-amylase, a secretory protein subject to proteolytic processing (cleavage of the N-terminal signal sequence) as well as glycosylation during its biosynthesis. The characterization and identification of the immunoprecipitable products synthesized were performed by SDS gel electrophoresis and subsequent fluorography. The molecular weight of the alpha-amylase synthesized by the microsomes was found to be identical with that of the mature secretory form of the enzyme on the basis of electrophoretic mobilities. A significant portion of the enzyme molecules synthesized was shown to be segregated into the microsomal vesicles and protected against digestion by endo-beta-N-acetylglucosaminidase, indicating that both proteolytic processing and glycosylation of the precursor polypeptide chains take place in the microsomes. The modification of the polypeptide chains was further examined by disrupting the microsomal membranes with Triton X-100. Detergent treatment of the microsomes prior to protein synthesis caused an inhibition of both proteolytic processing and glycosylation of the polypeptide chains, leading to the synthesis of the unprocessed nascent (precursor I), processed but nonglycosylated nascent (precursor II) forms, in addition to the mature form of alpha-amylase. Furthermore, the results of time-sequence analysis of the inhibitory effect of Triton X-100 on the modification of the polypeptide chains have led us to conclude that both proteolytic processing and subsequent glycosylation occur in the microsomes during the biosynthesis of alpha-amylase.

DISTRIBUTION OF α-AMYLASE IN THE TRITICALE KERNEL DURING DEVELOPMENT

1975 ◽  
Vol 55 (1) ◽  
pp. 29-36 ◽  
Author(s):  
W. DEDIO ◽  
D. H. SIMMONDS ◽  
R. D. HILL ◽  
H. SHEALY
Keyword(s):  
Triticum Aestivum ◽  
Secale Cereale ◽  
Microscopic Examination ◽  
Amylase Activity ◽  
Triticum Aestivum L ◽  
Alpha Amylase ◽  
Necrotic Tissue ◽  
Aleurone Cells ◽  
Development Period ◽  
Secale Cereale L

Seed of four triticale (Triticale hexaploide Lart.) cultivars, two wheat (Triticum aestivum L.) cultivars, and one rye (Secale cereale L.) cultivar were harvested at 4-day intervals from 6 to 42 days post-anthesis. Alpha-amylase activity was determined in the embryo, pericarp, aleurone, and endosperm of the seed. In all cases, the α-amylase activity in the embryo was low. The pericarp activity reached a maximum in all samples at approximately 10–15 days post-anthesis. Aleurone and endosperm activity remained low throughout the development period in all but one triticale cultivar. In triticale cultivar 6A 190, the aleurone and endosperm α-amylase activity remained low until approximately 20–25 days post-anthesis, at which point the activity increased to levels normally associated with sprouted grain. Light microscopic examination of the 6A 190 at 10 days post-anthesis showed that the starch in the inner portion of the pericarp was digested. At 22 days, all pericarp starch had disappeared. Specific lesions in the endosperm and aleurone cells were observed beyond 22 days. Areas of the endosperm where starch damage due to α-amylase could be seen were often associated with regions possessing necrotic tissue located between the aleurone and endosperm. In some areas, aleurone cells were completely absent.

scholarly journals The α-Amylase Induction in Endosperm during Rice Seed Germination Is Caused by Gibberellin Synthesized in Epithelium

2002 ◽  
Vol 128 (4) ◽  
pp. 1264-1270 ◽  
Author(s):  
Miyuki Kaneko ◽  
Hironori Itoh ◽  
Miyako Ueguchi-Tanaka ◽  
Motoyuki Ashikari ◽  
Makoto Matsuoka
Keyword(s):  
Seed Germination ◽  
Rice Seed ◽  
Amylase Induction

scholarly journals The Rice Alpha-Amylase, Conserved Regulator of Seed Maturation and Germination

2019 ◽  
Vol 20 (2) ◽  
pp. 450 ◽  
Author(s):  
Rebecca Damaris ◽  
Zhongyuan Lin ◽  
Pingfang Yang ◽  
Dongli He
Keyword(s):  
Seed Germination ◽  
Growth Period ◽  
Seed Maturation ◽  
Alpha Amylase ◽  
Research Progress ◽  
Carbohydrate Binding ◽  
Rice Seed ◽  
Crop Breeding ◽  
Developing Seed ◽  
Germination Process

Alpha-amylase, the major form of amylase with secondary carbohydrate binding sites, is a crucial enzyme throughout the growth period and life cycle of angiosperm. In rice, alpha-amylase isozymes are critical for the formation of the storage starch granule during seed maturation and motivate the stored starch to nourish the developing seedling during seed germination which will directly affect the plant growth and field yield. Alpha-amylase has not yet been studied intensely to understand its classification, structure, expression trait, and expression regulation in rice and other crops. Among the 10-rice alpha-amylases, most were exclusively expressed in the developing seed embryo and induced in the seed germination process. During rice seed germination, the expression of alpha-amylase genes is known to be regulated negatively by sugar in embryos, however positively by gibberellin (GA) in endosperm through competitively binding to the specific promoter domain; besides, it is also controlled by a series of other abiotic or biotic factors, such as salinity. In this review, we overviewed the research progress of alpha-amylase with focus on seed germination and reflected on how in-depth work might elucidate its regulation and facilitate crop breeding as an efficient biomarker.

Immunohistochemical localization of alpha-amylase in barley aleurone cells

1976 ◽  
Vol 20 (1) ◽  
pp. 183-198
Author(s):  
R.L. Jones ◽  
R.F. Chen
Keyword(s):  
Cell Wall ◽  
Wall Layer ◽  
Immunohistochemical Localization ◽  
Alpha Amylase ◽  
Perinuclear Region ◽  
Nuclear Region ◽  
Aleurone Cells ◽  
Rabbit Igg ◽  
Barley Aleurone ◽  
Aleurone Tissue

Alpha-Amylase was localized in aleurone cells of barley using immunohistochemical methods. Anti-alpha-amylase antibody was produced by rabbits immunized with enzyme purified from malt diastase and Himalaya variety barley seeds. Immunoelectrophoresis showed that the antibodies to both antigens were immunologically similar, therefore, they were used interchangeably in the localization of alpha-amylase. Fluorescence of 8–10 mum sections of freeze-substituted and paraffin embedded, gibberellic acid (GA)-treated aleurone tissue incubated with rabbit anti-alpha-amylase IgG and rhodamine-conjugated goat-anti-rabbit IgG is localized in the cytoplasm, the nuclear region and the innermost portion of the cell wall. Cytoplasmic immunofluorescence is not associated with a specific organelle but rather is diffusely distributed. The fluorescence of the nuclear region, however, is intense and in thinner (4-5 mum) sections is associated not with the nucleoplasm but with the nuclear envelope and perinuclear region of the cytoplasm. Fluorescence of the cell wall is confined to the inner boundary of the wall corresponding to the resistant wall layer. The immunofluorescent properties of non-GA-treated cells are quantitatively different; fluorescence of these sections is low and diffuse and is particularly reduced in the nuclear region. Electron microscopy shows that GA-treatment results in the proliferation of endoplasmic reticulum (ER) in the perinuclear region of the cell. We suggest that the alpha-amylase localized by immunofluorescence in the perinuclear region of the cell is localized in this ER produced in response to GA treatment. Immunohistochemical localization of alpha-amylase in cells zonated by centrifugation also suggests that the enzyme is intimately associated with the perinuclear area.

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