Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.)--University of Virginia, 1999. / Spine title: RSV & CTL responses. Includes bibliographical references (p. 143-185). Also available online through Digital Dissertations.

Thesis (Ph.D.) - University of Queensland, 2003. / Includes bibliography.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 196-235).

Surfactin, a lipopeptide surfactant and antibiotic produced by Bacillus subtilis, exhibits a strong membrane perturbation. One of the drawbacks hindering its commercial applications is the unknown mechanism of surfactin self-resistance in the producer. Therefore, the aim of this study was to examine the self-protective mechanisms of the cytoplasmic membrane of B. subtilis against the deleterious effect of surfactin. In order to reach this task, two isogenic pairs of strains differing only in surfactin production were constructed. It was found out that the early response of the producer is realized by increasing the amount of total lipid content in the membrane already with the onset of surfactin synthesis. This process leads to lowering the surfactin-lipid ratio in the membrane. In parallel with the growing surfactin concentration the content of anionic phospholipids with cardiolipin as the major representative rises up to 24 % of the total. Together with the fall of phosphatidylethanolamine these changes promote the membrane stabilization and protect it against the interaction with surfactin. These alterations result in higher rigidity both of the polar head and hydrophobic chain region of the membrane as the steady state anisotropy of DPH and TMA-DPH showed. After 24 h of cultivation induction of...

Cytoplasmic membrane adaptation to surfactin in Bacillus subtilis 168 non-producing strain Surfactin, the most potent surface active compound and antibiotic is produced by bacteria of the genus Bacillus. Surfactin interacts with membrane bilayers, that results in destabilization and permeabilization of this structure. However mechanism of surfactin self-resistance in the producer's membrane is not understood. The aim of this study was to characterize the adaptive processes occurring at the level of cytoplasmic membrane of surfactin non-producing strain B. subtilis 168, which was exposed to exogenously added surfactin during the exponential phase of growth. The cultivation protocol of B. subtilis growth on agar media plates supplemented with surfactin was developed. Two surfactin concentrations that inhibit (400 g/ml) and even stimulate (300 g/ml) the growth of B. subtilis 168 strain were assessed. Surfactin brought about the growth arrest for 3 hours and the restored growth rate decreased in the case of inhibitory concentration, whereas the stimulatory concentration increased the growth rate and resulted in higher final density of the population. TLC was performed to analyze the polar head groups of membrane phospholipids. The portion of phosphatidylserine was found to increase at both surfactin...

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20757号 / 医博第4287号 / 新制||医||1024(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 生田 宏一, 教授 濵﨑 洋子, 教授 髙折 晃史 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.