Concerning Flagellation and Motility

H. J. Conn, R. P. Elrod
1947 Journal of Bacteriology  
In certain recent papers Pijper (1946 Pijper ( , 1947 has proposed the thesis that bacterial flagella are not organs of locomotion but are artifacts produced on the drying of a carbohydrate envelope surrounding the cell. He regards this as the explanation of much disagreement which has occurred in the literature about the type of flagellation shown by any given species and insists that since flagella are mere artifacts their arrangement around the cell is of no significance. Some time ago one
more » ... Some time ago one of the present authors (Conn, 1938) proposed an entirely different theory to account for the bacterial species that were declared peritrichic by some students, monotrichic by others; namely, that some species are neither constantly peritrichic nor truly monotrichic, but that they show "degenerate peritrichic flagellation," some strains having only one flagellum, others two or three flagella, but never a tuft or two or three at one pole. The present investigation was undertaken partly in the hope that the electron microscope would shed some light on the subject and partly with the idea of using Pijper's technique on a different motile organism. CULTURES SELECTED FOR STUDY When the idea of degenerate peritrichic flagellation was advanced, it was indicated as being especially well represented by species of the genera Agrobacterium, Rhizobium, and Chromobacterium. Accordingly, for the present electron microscope study representatives of these genera were selected as follows: Agrobacterium tumefaciens (Smith and Townsend) Conn (the type species of the genus); Agrobacterium radiobacter (Beijerinck and Van Delden) Conn; Agrobacterium rhizogenes (Riker et al.) Conn; strains of Rhizobium from pea, clover, and alfalfa nodules; two strains of Chromobacterium spp. (violet bacteria, Cruess-Callaghan's nos. 17 and 19). As organisms for use in trying the Pijper technique, Escherichia coli and Bacillus cereus were selected. TECHNIQUE FOR PREPARING MOUNTS FOR THE ELECTRON MICROSCOPE It has been our experience, and that of others, that any excessive manipulation of bacterial material in preparing mounts for the electron microscope invariably results in mutilation. Therefore, although a few of the pictures represented here were taken of organisms prepared in the usual way (distilled water preparations I Journal Paper
doi:10.1128/jb.54.6.681-687.1947 fatcat:ztbavklcljfyroqx6ehidqewou