GENETIC STUDY ON BACTERIAL COLONY FORMATION USING A COLONIZATION-DEFECTIVE MUTANT

2015 Fiscal Year Final Research Report

• Project/Area Number: 24380044
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Applied microbiology
• Research Institution: The University of Tokyo
• Principal Investigator: MASAKI HARUHIKO 東京大学, 農学生命科学研究科, 教授 (50134515)
• Co-Investigator(Kenkyū-buntansha): SHIGEMATSU Toru 新潟薬科大学, 応用生命科学部, 教授 (10315286)
• Project Period (FY): 2012-04-01 – 2016-03-31
• Keywords: バクテリア / 大腸菌 / 温度感受性変異 / コロニー / 増殖 / 固体培養 / 液体培養 / 不飽和脂肪酸

Outline of Final Research Achievements

Colony formation is a basic method for bacterial isolation and counting. But most natural live bacteria cannot be cultured due to low colony formation. Obviously being alive does not mean being able to form colonies, however, the difference is little understood in terms of gene expression. To gain a genetic insight into colony formation, we isolated a colonization-defective Escherichia coli mutant. The mutant was unable to synthesize unsaturated fatty acids. This mutant requires oleic acid for growth, but with a limited supply of oleic acid, its growth on solid medium was more sensitively and seriously impaired than in liquid medium. Enxymatical inhibition of fatty acid synthesis by cerulenin also impaired growth more seriously in solid cultures than liquid cultures of both wild-type E. coli and Bacullus subtilis. The depletion of fatty acids in the environment is probably one of the causes of low colony formation, which can be improved by fatty acid supplementation.

Free Research Field

農芸化学、微生物学、生化学