| Project/Area Number |
14360163
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied animal science
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SAKAI Senkiti The University of Tokyo, Graduate School of Agricultural and life Sciences, Professor, 大学院・農学生命科学研究科, 教授 (80114487)
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| Co-Investigator(Kenkyū-buntansha) |
IMAKAWA Kazuhiko The University of Tokyo, Graduate School of Agricultural and life Sciences, Associate Professor, 大学院・農学生命科学研究科, 助教授 (00291956)
AOKI Fugaku The University of Tokyo, Graduate School of Agricultural and life Sciences, Associate Professor, 大学院・新領域創成科学研究科, 助教授 (20175160)
ITO Kikuji The University of Tokyo, Graduate School of Agricultural and life Sciences, Associate Professor, 大学院・農学生命科学研究科, 助教授 (50100045)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥17,000,000 (Direct Cost: ¥17,000,000)
Fiscal Year 2003: ¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 2002: ¥10,700,000 (Direct Cost: ¥10,700,000)
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| Keywords | L-amino acid oxidase / H_2O_2 generating enzyme / mastitis / mouse milk / cow milk / killing bacteria / ラクトパーオキシダーゼ / 殺菌作用 / ホルモンによる制御機構 / 過酸化水素感受性細菌 / 発生期酸素感受性細菌 / 過酸化水素 |
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| Research Abstract |
L-Amino acid oxidase (LAO) and lactoperoxidase (LPO) of mouse milk are separated by gel-filtration chromatography.LAO generates H_2O_2 in the presence of L-amino acids and subsequently, LPO generates O through the degradation of H_2O_2. Milk is capable of producing the bacterial toxic H_2O_2 and O The quantity of H_2O_2 was around 300 μmoles/ml milk. In order to examine whether or not LAO and LPO is responsible for killing bacteria in the mammary gland, bacteria (Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Streptococcus agalactiae) are isolated from bovine mastitis milk and cultured with LAO in the presence and absence of LPO. In the presence of L-amino acids, LAO inhibits the growth of Klebsiella pneumoniae and Escherichia coli, and kills Staphylococcus aureus. Streptococcus agalactiae grows normally in the presence of LAO and does not grow in the presence of LAO and LPO. Thus, we divide them into two types : one being H_2O_2-sensitive and the other being O^-sensitive. It is concluded that H_2O_2 and O^-generated in milk is able to prevent the growth of bacteria in the mouse mammary gland.
Cow milk of Holstein and Japanese Black breeds are collected and separated by gel-filtration chromatography. The H_2O_2 generating enzyme is appeared at the peak fraction of 75, being a molecular weight of about 10 k. The eluting profiles of the two breeds are identical. The quantity.of this enzyme in milk is small at early lactation and at late lactation, but is relatively high at mid-lactation. By the incubation for 2 hr at 37℃, the enzyme generates H_2O_2 about 5-fold as compared to that of the 0 hr-incubation.
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