{"created":"2021-03-01T06:08:30.593717+00:00","id":4690,"links":{},"metadata":{"_buckets":{"deposit":"ae519fb4-c123-4e80-8d6f-ab19bf27fc0a"},"_deposit":{"id":"4690","owners":[],"pid":{"revision_id":0,"type":"depid","value":"4690"},"status":"published"},"_oai":{"id":"oai:niigata-u.repo.nii.ac.jp:00004690","sets":["453:455","468:563:564"]},"item_6_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"イネα-アミラーゼの機能発現に関する研究"}]},"item_6_biblio_info_6":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2005-09-20","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"146","bibliographicPageStart":"1","bibliographic_titles":[{}]}]},"item_6_date_granted_51":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2005-09-20"}]},"item_6_degree_grantor_49":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"新潟大学"}]}]},"item_6_degree_name_48":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（農学）"}]},"item_6_description_4":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"The aim of this reserch is clarify details of funtional expression of α-amylase in rice. Studies of suspension-cultured cell system provided evidences that phosphate is a potent stimulator for α-amylase secretion and starch degradation. Studies of transgenic rice plants with suppressed expression or overexpression of α-amylase showed that α-amylase is involved in degradation of plastidial starch in living cells. These results indecate that there exist multi-subcellular localization of α-amylase encoded by single gene in rice. Furthermore, α-amylase I-1 fused with green fluorescence protein was targeted into the plastids in bombarded onion epidermal cells, indicating that rice α-amylase I-1 molecule contains a plastid targeting signal common to both rice and onion cells. The cotents are follows. Novel Regulatory Factor for α-Amylase Secretion and Stach Degradation in Rice Cell Culture Effects of phosphate on the Ca2+ uptake and the sucrose-controlled secretion of α-amylase molecules in cultured cells were investigated, Phosphate markedly stimulated Ca2+ uptake into rice cells, particulary at the outer cell layer of the cell cluster. Phosphate at 10 mM was found to increse the synthesis and extracelluar liberaton of α-amylase II-4 molecules in the sucrose-supplemented cells. The distribution pattern of enzyme in rice cell clusters induced by phosphate was similar to that of Ca2+ uptake, Phosphate did not increase the level of mRNA of α-amylase II-4, indicating that phosphate stimulates the translation and posttranslational secretory processes of α-amylase II-4 molecules in the presence of sucrose. Furthermore, phosphate enhanced both the Ca2+ uptake and α-amylase II-4 synthesis in the microsomes. These results strongly suggested that the ratio of phosphate to sugar is important for regulating the Ca2+ uptake, and that phosphate and sugar precisely coordinate the Ca2+-mediated synthesis and extracelluar liberation of α-amylase II-4 molecules in rice cells. In addition, phosphate reduced the starch content in rice cells, same as the sugar-starved cells. The results may indicate that α-amylase plays a role for degrading starch in living cells. Involment of α-Amylase in Starch Degradation in Rice Plastids To determine role of α-amylase isoform I-1 in the degradation of starch in rice leaf chloroplasts, I renerated a series of transgenic rice plants with suppressed expression of α-amylase I-1. In the lines with suppressed expression or overexpression of α-amylase I-1 at both mRNA and protein levels, seed germinaton and seedling growth were markedly delayed in comparison with those in the wild-type plants.","subitem_description_type":"Abstract"},{"subitem_description":"Houever, the growth retardation was overcome by supplementation of sugars. Interestingly, a significant increse of starch accumulation in the young leaf tissues was observed under a sugar-supplemented condition. In contrast, the starch content of leaves was reduced in the plants overexpressinf α-amylase i-1. In immunocytochemicalanalysis with specific anti-α-amylase I-1 antiserum, immuno-gold particles deposited in the choroplasts and estracellular space in young leaf cells. I further examined the expression and targeting of α-amylase I-1 fused with the green fluorescent protein in re-differentiated green cells, and showed that the fluorescence of expressed fusion protein co-localized with the chlorophyll autofluorescence in the transgenic cells. In addition, mature protein species of α-amylase I-1 bearing an oligosaccharide side chain were detected in the isolated chloroplasts. Based on these results, I concluded that α-amylase I-1 targets the chloroplasts through the ER-Golgi system and plays a significant role in the starch degradation in rice leaves. Overexpression of α-Amylase affects Starch accumulation in Ripening Seeds of Rice To determine physiological function of α-amylase isoform II-4, I generated a series transgenic rice plants with overexpression of α-amylase II-4. In the line with overexpression of α-amylase II-4 at both the mRNA and protein levels, the ability of seed germination and seedling growth was unaltered. Unlike α-amylase I-1, starch accumulation in leaf tissues overexpressing α-amylase II-4 was scarcely changed. However, the seeds produced in the transgenic rice plants exhibited an abnormal accumulation of starch, as well as that in rice overexpressing α-amylase I-1. Based on these in endosperm of ripening seed and controls accumulation of reserve stach in rice.","subitem_description_type":"Abstract"}]},"item_6_description_5":{"attribute_name":"内容記述","attribute_value_mlt":[{"subitem_description":"新大院博（農）甲第63号","subitem_description_type":"Other"}]},"item_6_description_53":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"新大院博（農）甲第63号","subitem_description_type":"Other"}]},"item_6_dissertation_number_52":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"13101甲第2530号"}]},"item_6_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"48906","nameIdentifierScheme":"WEKO"}],"names":[{"name":"浅妻, 悟"}]}]},"item_6_publisher_7":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"新潟大学大学院自然科学研究科"}]},"item_6_select_19":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_select_item":"author"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Asatsuma, Satoru"}],"nameIdentifiers":[{"nameIdentifier":"48905","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2019-08-05"}],"displaytype":"detail","filename":"13_0033.pdf","filesize":[{"value":"31.3 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"本文","url":"https://niigata-u.repo.nii.ac.jp/record/4690/files/13_0033.pdf"},"version_id":"ea5cde59-d998-41f8-bd20-79b88638ca96"}]},"item_keyword":{"attribute_name":"キーワード","attribute_value_mlt":[{"subitem_subject":"α-Amylase","subitem_subject_scheme":"Other"},{"subitem_subject":"chloroplast","subitem_subject_scheme":"Other"},{"subitem_subject":"transgenic plant","subitem_subject_scheme":"Other"},{"subitem_subject":"α-アミラーゼ","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"葉緑体","subitem_subject_language":"en","subitem_subject_scheme":"Other"},{"subitem_subject":"トランスジェニック植物","subitem_subject_language":"en","subitem_subject_scheme":"Other"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Studies on Functional Expression of α-Amylase in Rice","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Studies on Functional Expression of α-Amylase in Rice"},{"subitem_title":"Studies on Functional Expression of α-Amylase in Rice","subitem_title_language":"en"}]},"item_type_id":"6","owner":"1","path":["455","564"],"pubdate":{"attribute_name":"公開日","attribute_value":"2007-04-23"},"publish_date":"2007-04-23","publish_status":"0","recid":"4690","relation_version_is_last":true,"title":["Studies on Functional Expression of α-Amylase in Rice"],"weko_creator_id":"1","weko_shared_id":2},"updated":"2022-12-15T03:37:32.420580+00:00"}