Characterization of lateral flagella of Selenomonas ruminantium

Abstract

Selenomonas ruminantium produces a tuft of flagella near the midpoint of the cell body and swims by rotating the cell body along the cell's long axis. The flagellum is composed of a single kind of flagellin, which is heavily glycosylated. The hook length of S. ruminantium is almost double that of Salmonella.

Fig. 1.

Electron microscopic images of Selenomonas ruminantium. Cells were grown in the absence of glucose (−glucose, left) or in the presence of glucose (+glucose, right).

Fig. 2.

Distribution of flagella on a cell. (A) Electron microscopic image of a cell that was osmotically shocked and stained with 1% phosphotungstic acid (PTA). The flagellar form is coiled (left). Enlarged image of the left panel showing flagellar basal bodies in the membranes (right). (B) Schematic presentation showing how the positions of flagella on a cell were measured. (C) Diagram of the distributions of sites of flagellar protrusion on a cell for S. ruminantium (left) and R. sphaeroides (right). The total numbers of flagella counted were 50 and 127, respectively.

Fig. 3.

Flagellar polymorphic transition. (A) Dark-field microscopic images of polymorphs observed under various pH and salt conditions. The upper side of the helix was focused to show the handedness. (B) Schematic phase diagram of polymorphs observed at different pHs and NaCl concentrations.

Fig. 4.

The S. ruminantium flagellin is glycosylated. (A) SDS gel pattern of an S. ruminantium flagellin. First lane, molecular size marker; second lane, single band of flagellin. (B) Detection of glycosylation of an S. ruminantium flagellin (lanes 3 and 6). Salmonella SJW1103 flagellin was used as a negative control (lanes 1 and 4), and Azospirillum flagellin was used as a positive control (lanes 2 and 5). Coomassie brilliant blue (CBB) staining (left) and PAS staining (right) of the purified flagellins are shown.

Fig. 5.

Amino acid sequence deduced from the S. ruminantium fliC1 gene. The underlined sequences were obtained by an analysis of purified FliC.

Fig. 6.

Shape and length of the hook. (A) Electron microscopic images of the hook basal body isolated from S. ruminantium. The desalted samples were stained with 2% PTA at pH 7.0. (B) Polymorphs of the hook under different pH conditions.