title: Clostridium perfringensα-toxin interaction with red cells and model membranes.
abstract: The effects of Clostridium perfringensα-toxin on host cells have previously been studied extensively but the biophysical processes associated with toxicity are poorly understood. The work reported here shows that the initial interaction between the toxin and lipid membrane leads to measurable changes in the physical properties and morphology of the membrane. A Langmuir monolayer technique was used to assess the response of different lipid species to toxin. Sphingomyelin and unsaturated phosphatidylcholine showed the highest susceptibility to toxin lypolitic action, with a two stage response to the toxin (an initial, rapid hydrolysis stage followed by the insertion and/or reorganisation of material in the monolayer). Fluorescence confocal microscopy on unsaturated phosphatidylcholine vesicles shows that the toxin initially aggregates at discrete sites followed by the formation of localised "droplets" accumulating the hydrolysis products. This process is accompanied by local increases in the membrane dipole potential by about 50 (±42) mV. In contrast, red blood cells incubated with the toxin suffered a decrease of the membrane dipole potential by 50 (±40) mV in areas of high toxin activity (equivalent to a change in electric field strength of 10(7) V m(-1)) which is sufficient to affect the functioning of the cell membrane. Changes in erythrocyte morphology caused by the toxin are presented, and the early stages of interaction between toxin and membrane are characterised using thermal shape fluctuation analysis of red cells which revealed two distinct regimes of membrane-toxin interaction.
authors: School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK. p.g.petrov@exeter.ac.uk.
authors: S A
authors: SA
authors: Jewell
authors: R W
authors: RW
authors: Titball
authors: J
authors: J
authors: Huyet
authors: C E
authors: CE
authors: Naylor
authors: A K
authors: AK
authors: Basak
authors: P
authors: P
authors: Gologan
authors: C P
authors: CP
authors: Winlove
authors: P G
authors: PG
authors: Petrov
mesh_terms: D001427:Bacterial Toxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003016:Clostridium perfringens / Q000378:metabolism*; D004912:Erythrocytes / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D006834:Hydrazines / Q000737:chemistry; D006868:Hydrolysis; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D018613:Microscopy, Confocal; D010713:Phosphatidylcholines / Q000737:chemistry; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013109:Sphingomyelins / Q000737:chemistry; D010738:Type C Phospholipases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C417561:Alexa 488 hydrazide; D001427:Bacterial Toxins; D002135:Calcium-Binding Proteins; D006834:Hydrazines; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D011994:Recombinant Proteins; D013109:Sphingomyelins; D010738:Type C Phospholipases; C040649:alpha toxin, Clostridium perfringens