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Results reveal the presence of two new of the four flagellins in Methanococcus voltae. The flagellin FlaA is distributed throughout the filament whereas FlaB3 appears to be seen in the proximal end of the cell surface, perhaps similar to the bacterial hook. Both FlaA and FlaB3 are structural components of the flagella.

Summarizes information presented at the Fifth Biennial Conference on Bacterial Locomotion and Signal Transduction on January 16-21, 1999. Two-component regulatory systems that control chemotactic behavior and gene expression in response to environmental signals; Quorum sensing; Behavior on surfaces; Flagellar structure and assembly; Diversity of taxis processes.

Examines the flagellar filament structure and cell motility of Salmonella typhimurium mutants lacking a part of the outer domain of flagellin. Isolation of mutants which can swim in the presence of antifilament antibodies; Morphology of flagellins isolated from the mutant types; Deletions in the flagellin structure; Role of the flagellin in cell motility.

Describes the polymorphic forms of the flagellar filament of Rhodobacter sphaeroides induced in vitro by changes in pH and ionic strength. Sequence analysis and expression studies on the fliC gene, which encodes the flagellin protein of R. sphaeroides; Control of the fliC gene by a sigma[sup 28]-dependent promoter.

Glycosylation is a posttranslational modification utilized in all three domains of life. Compared to eukaryotic and bacterial systems, knowledge of the archaeal processes involved in glycosylation is limited. Recently, Methanococcus voltae flagellin proteins were found to have an N-linked trisaccharide necessary for proper flagellum assembly. Current analysis by mass spectrometry of Methanococcus maripaludis flagellin proteins also indicated the attachment of an N-glycan containing acetylated sugars. To identify genes involved in sugar biosynthesis in M. maripaludis, a putative acetyltransferase was targeted for in-frame deletion. Deletion of this gene (MMP0350) resulted in a flagellin molecular mass shift to a size comparable to that expected for underglycosylated or completely nonglycoslyated flagellins, as determined by immunoblotting. Assembled flagellar filaments were not observed by electron microscopy. Interestingly, the deletion also resulted in defective pilus anchoring. Mutant cells with a deletion of MMP0350 had very few, if any, pili attached to the cell surface compared to a nonflagellated but piliated strain. However, pili were obtained from culture supernatants of this strain, indicating that the defect was not in pilus assembly but in stable attachment to the cell surface. Complementation of MMP0350 on a plasmid restored pilus attachment, but it was unable to restore flagellation, likely because the mutant ceased to make detectable flagellin. These findings represent the first report of a biosynthetic gene involved in flagellin glycosylation in archaea. Also, it is the first gene to be associated with pili, linking flagellum and pilus structure and assembly through posttranslational modifications. [ABSTRACT FROM AUTHOR]

The role of flagellin glycosylation on motility was investigated in Pseudomonas syringae pv. tabaci. The swimming activity of glycosylation-defective mutants was prominently decreased in a highly viscous medium. The mutants showed differences in polymorphic transitions and in the bundle formation of flagella, indicating that glycosylation stabilizes the filament structure and lubricates the rotation of the bundle. [ABSTRACT FROM AUTHOR]

Three flagellar proteins, FliG, FliM, and FliN (FliGMN), are the components of the C ring of the flagellar motor. The genes encoding these proteins are multifunctional; they show three different phenotypes (Fla-, Mot-, and Che-), depending on the sites and types of mutations. Some of the Mot- mutants previously characterized are found to be motile. Reexamination of all Mot- mutants in fliGMN genes so far studied revealed that many of them are actually temperature sensitive (TS); that is, they are motile at 20°C but nonmotile at 37°C. There were two types of TS mutants: one caused a loss of function that was not reversed by a return to the permissive temperature (rigid TS), and the other caused a loss that was reversed (hyper-TS). The rigid TS mutants showed an all-or-none phenotype; that is, once a structure was formed, the structure and function were stable against temperature shifts. All of fliM and fliN and most of the fliG TS mutants belong to this group. On the other hand, the hyper-TS mutants (three of the fliG mutants) showed a temporal swimming/stop phenotype, responding to temporal temperature shifts when the structure was formed at a permissive temperature. Those hyper-TS mutation sites are localized in the C-terminal domain of the FliG molecules at sites that are different from the previously proposed functional sites. We discuss a role for this new region of FliG in the torque generation of the flagellar motor. [ABSTRACT FROM AUTHOR]