{"created":"2023-06-19T10:29:12.743832+00:00","id":8947,"links":{},"metadata":{"_buckets":{"deposit":"85598691-4fc8-4691-a0f1-7d8704b260f5"},"_deposit":{"created_by":18,"id":"8947","owners":[18],"pid":{"revision_id":0,"type":"depid","value":"8947"},"status":"published"},"_oai":{"id":"oai:muroran-it.repo.nii.ac.jp:00008947","sets":["41:227"]},"author_link":["42158"],"item_81_date_granted_17":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2016-03-23"}]},"item_81_degree_grantor_10":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"室蘭工業大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"Muroran Institute of Technology"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"10103","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_81_degree_name_11":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（工学）","subitem_degreename_language":"ja"}]},"item_81_description_25":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_81_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"磁性細菌（magnetotactic bacteria, MTB）は、環境の地磁気線に応じて移動する細菌である。MTBの菌体内で大きさが35～120 nmの磁性ナノ粒子（magnetic nanoparticles, MNPs；マグネタイト（Fe3O4）またはグレガイト（Fe3S4））が形成される。MNPsのそれぞれは、リン脂質二重層に囲まれていて15～20個並んだ「マグネトソーム（magnetosome）」と呼ばれるチェーン構造を形成している。初期に単離培養されたMTBはMagnetospirillum magnetotacticum MS-1で、単磁区で高純度のFe3O4の結晶を生成する。本博士論文は、異なるFe3+の濃度及び異なる遷移金属元素（Fe/Zn/Co）を含む培地で培養したMTB株MS-1で合成されるマグネタイトの磁気特性をMPMSで調べたものである。主要な結果は以下のどおりである。まず、異なるFe3+の濃度の影響について述べる。MS-1細胞の総量は培地中の初期Fe3+の濃度と関係がなかったが、Fe3+の濃度が上がるにつれ、磁石に引きつけられる細胞の量が多くなることが分かった。培地中のFe3+が34 μMのとき、保磁力（Hc）と飽和磁化（Ms）の最大値が観察された。Verwey転移温度（TV）とブロッキング温度（TB）（TV <TB）との関係は、培地中の初期のFe3+濃度と関係なく、MS-1細胞の増加に伴い、MNPがチェーン状に配置されていることを示唆している。これらの結果は、マグネタイトの磁気特性は培地中のFe3+の濃度にわずかであるが影響されることを示唆する。次に、異なる遷移金属元素（Fe/Zn/Co）を含む培地を用いた結果について述べる。MS-1細胞の成長速度は培地中のFe、Zn あるいはCoに影響されないが、合成されるマグネトソームのサイズがZn 或はCo 培地では小さくなる。Hc、Ms、TV、TB値の変化から見て、細胞全体（IC）、マグネトソーム（MG）とマグネタイト（MT）における磁気特性がZn或はCo に影響されることが分かった。 Znを含む培地では、IC、MGとMTのMs 値が低下する。そして、ICとMG のHc 値は標準Feのそれと比べ有意差がなかったが、MTのHc値が大きくなった。また、標準FeのTVと比べて、IC、MGとMTのTV値には変化がなかったが、IC、MGのTB 値は大きくなった。MTのTB値には変化がなかった。Coを含む培地では、標準FeのHc値と比べてIC、MG と MT におけるHc値が大きくなった。Ms値がIC、MGで低下したが、MTでは大きな変化がなかった。また、TVとTB値はどちらの培地でも検出できなかった。以上の結果は、培地中のCoやZnがマグネタイト中に微量取り込まれたことを示唆していると考えられる。","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"Magnetotactic bacterium (MTB) is a class of bacterium which tends to move in response to the environment's geomagnetic lines. MTB forms magnetic nanoparticles (MNPs: e.g. magnetite Fe3O4 or greigite Fe3S4) with a size of 35-120 nm in vivo. Each of MNPs is surrounded by a phospholipid bilayer. They form a chain structure composed of 15-20 MNPs, which is called “magnetosome”. The first MTB strain isolated and cultured was Magnetospirillum magnetotacticum MS-1, which produces highly pure Fe3O4 crystals with a single magnetic domain. My doctoral thesis is a summary of an investigation of the magnetic properties of magnetite synthesized by MTB strain MS-1 cells grown with different concentrations of ferric (Fe3+) iron or with different conditions of transition metal element (Fe/Zn/Co). The results were as follows: The total yield of magnetic cells of MS-1 increased with the increase of the initial Fe3+ concentrations, even though the total yield of the MS-1 cells was independent on the initial Fe3+ concentrations. The maximum coercivity (Hc) and saturation magnetization (Ms) values were observed at Fe3+ concentration of 34 μM. The relationship between Verwey transition temperature (TV) and Blocking temperature (TB) (TV < TB) of dried cells suggested that MNPs were arranged in chain when MS-1 cells were grown with the different initial Fe3+ concentration. The above results illustrated that the initial Fe3+ concentration had a marginal effect on the magnetic properties of MTB strain MS-1, except for the medium without addition of Fe3+. In the growth medium (GM) containing transition metal element (Fe/Zn/Co), the growth rate of MS-1 cells was not significantly different. The size of magnetosome became smaller in the GM with Fe/Zn or Fe/Co than that in the GM with Fe. The change in Ms, Hc, TV, TB suggested that the magnetic properties of intact cell (IC), magnetosome (MG) and magnetite (MT) was influenced by Zn or Co. In the GM with Fe/Zn, the Ms value of IC, MG and MT was decreased. Hc value of IC and MG was not significantly different with Fe culture, but that of MT was increased. Also, the TV was not significantly different from that of the GM with Fe in IC, MG and MT, but the TB value of IC and MG was increased. The TB of MT unchanged. In the GM with Fe/Co, the Hc value of IC, MG and MT increased and Ms in IC or MG decreased. Ms value of MT was not significantly different from the value of Fe. TV and TB were not detected.","subitem_description_language":"en","subitem_description_type":"Abstract"}]},"item_81_dissertation_number_13":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第385号"}]},"item_81_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15118/00008930","subitem_identifier_reg_type":"JaLC"}]},"item_81_subject_9":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"465","subitem_subject_scheme":"NDC"}]},"item_81_text_12":{"attribute_name":"学位の種別","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"課程博士"}]},"item_81_text_14":{"attribute_name":"報告番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"甲第385号"}]},"item_81_text_15":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"博甲第385号"}]},"item_81_text_16":{"attribute_name":"研究科・専攻","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"創成機能工学専攻"}]},"item_81_version_type_24":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorAffiliations":[{"affiliationNameIdentifiers":[],"affiliationNames":[{"affiliationName":""}]}],"creatorNames":[{"creatorName":"YI, Riletu","creatorNameLang":"en"},{"creatorName":"イ, ロルト","creatorNameLang":"ja"}],"familyNames":[{},{}],"givenNames":[{},{}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2016-06-08"}],"displaytype":"detail","filename":"A385_summary.pdf","filesize":[{"value":"552.1 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A385_summary","objectType":"abstract","url":"https://muroran-it.repo.nii.ac.jp/record/8947/files/A385_summary.pdf"},"version_id":"9c128c22-0899-4000-aa6e-c1a93669adab"},{"accessrole":"open_access","displaytype":"detail","filename":"A385.pdf","filesize":[{"value":"4.3 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"objectType":"fulltext","url":"https://muroran-it.repo.nii.ac.jp/record/8947/files/A385.pdf"},"version_id":"ed2db201-be98-446a-ba5e-135e67c66fbd"}]},"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":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"Study on the magnetic properties of magnetite synthesized by Magnetospirillum magnetotacticum MS-1","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Study on the magnetic properties of magnetite synthesized by Magnetospirillum magnetotacticum MS-1","subitem_title_language":"en"},{"subitem_title":"磁性細菌Magnetospirillum magnetotacticum MS-1により合成されたマグネタイトの磁気特性についての研究","subitem_title_language":"ja"}]},"item_type_id":"81","owner":"18","path":["227"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2016-06-08"},"publish_date":"2016-06-08","publish_status":"0","recid":"8947","relation_version_is_last":true,"title":["Study on the magnetic properties of magnetite synthesized by Magnetospirillum magnetotacticum MS-1"],"weko_creator_id":"18","weko_shared_id":-1},"updated":"2024-01-22T02:25:05.341806+00:00"}