title: Biogenesis of Lysobacter sp. XL1 vesicles.
abstract: The Gram-negative bacterium Lysobacter sp. XL1 forms vesicles and, using them, secretes an extracellular protein, bacteriolytic endopeptidase L5. Fractionation of a Lysobacter sp. XL1 vesicle preparation in a sucrose density gradient yielded four vesicle fractions of 30%, 35%, 40% and 45% sucrose. The size of most vesicles concentrated in 30% and 35% sucrose fractions were 40-65 and 65-100 nm, respectively. Electrophoresis and immunoblotting showed vesicles of the 30% fraction differed from those in the other fractions not only in density but also in protein content. Protein L5 was found to be secreted into the extracellular medium only by means of vesicles of the 30% sucrose fraction. Electron microscopic immunocytochemistry of Lysobacter sp. XL1 cells showed protein L5 to be distributed unevenly along the periplasmic space and to be concentrated in certain periplasmic loci adjacent to the outer membrane. It was in those loci where vesiculation occurred. A model of the formation of Lysobacter sp. XL1 vesicles is proposed based on the data obtained.
authors: Laboratory of Microbial Cell Surface Biochemistry, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Pr. Nauki, Pushchino, Moscow Region, 142290 Russia kudryakovairina@yandex.ru.
authors: Irina V
authors: IV
authors: Kudryakova
authors: Laboratory of Microbial Cytology, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Pr. Nauki, Pushchino, Moscow Region, 142290 Russia.
authors: Natalia E
authors: NE
authors: Suzina
authors: Laboratory of Microbial Cell Surface Biochemistry, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Pr. Nauki, Pushchino, Moscow Region, 142290 Russia.
authors: Natalia V
authors: NV
authors: Vasilyeva
mesh_terms: D001433:Bacteriolysis; D021961:Cell Membrane Structures / Q000378:metabolism* / Q000648:ultrastructure; D002499:Centrifugation, Density Gradient; D010450:Endopeptidases / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D053528:Lysobacter / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure*; D008854:Microscopy, Electron
chemical_list: D010450:Endopeptidases
keywords: Lysobacter sp. XL1; biogenesis of outer membrane vesicles; heterogeneity of outer membrane vesicles; lytic endopeptidase L5; vesicle biogenesis factors