Biogenesis of the flagellum, a motive organelle of many bacterial species, is best understood for members of the Enterobacteriaceae. The flagellum is a heterooligomeric structure that protrudes from the surface of the cell. Its assembly initially involves the synthesis of a dedicated protein export apparatus that subsequently transports other flagellar proteins by a type III mechanism from the ...

Trypanosoma brucei is a uni-cellular protist that causes African sleeping sickness. These parasites have a flagellum that is attached to the cell body and is indispensible for its motility. The flagellum consists of a canonical 9+2 axoneme and a paraflagellar rod (PFR), an intricate tripartite, fibrous structure that is connected to the axoneme. In this paper we describe results from cryo-elect...

Bacterial flagella assume different helical shapes during the tumbling phase of a bacterium but also in response to varying environmental conditions. Force-extension measurements by Darnton and Berg explicitly demonstrate a transformation from the coiled to the normal helical state (N.C. Darnton, H.C. Berg, Biophys. J. 92, 2230 (2007)). We here develop an elastic model for the flagellum based o...

The genus Phalansterium, which contains three named species, was created by Cienkowski (1870) for Monas consociatum Fresenius 1858. Ph. digitatum Stein 1878 from freshwater and Ph. solitarium Sandon 1924 from soil were later been added to the genus. Hibberd (1983) considered it possible that Phalansterium consociatum and Ph. digitatum are conspecific. As defined by light microscopy, members of ...

The bacterial flagellum is a self-assembling nanomachine. The external flagellar filament, several times longer than a bacterial cell body, is made of a few tens of thousands subunits of a single protein: flagellin. A fundamental problem concerns the molecular mechanism of how the flagellum grows outside the cell, where no discernible energy source is available. Here, we monitored the dynamic a...

We have recorded spiking responses from single, bimodally sensitive local interneurons (Type I) in the crayfish deutocerebrum to hydrodynamic and odorant stimuli flowing in two directions past the lateral antennular flagellum. Changing the direction of seamless introductions (meaning, with minimal variations of fluid velocity magnitude) of odorant flow past the flagellum, from proximal-->distal...

During the Leishmania life cycle, the flagellum undergoes successive assembly and disassembly of hundreds of proteins. Understanding these processes necessitates the study of individual components. Here, we investigated LdFlabarin, an uncharacterized L. donovani flagellar protein. The gene is conserved within the Leishmania genus and orthologous genes only exist in the Trypanosoma genus. LdFlab...

Cilia and flagella are model systems for studying how mechanical forces control morphology. The periodic bending motion of cilia and flagella is thought to arise from mechanical feedback: dynein motors generate sliding forces that bend the flagellum, and bending leads to deformations and stresses, which feed back and regulate the motors. Three alternative feedback mechanisms have been proposed:...

Tssk4 belongs to the Testis Specific Serine/threonine protein Kinase (TSSK) family, members of which play an important role in spermatogenesis and/or spermiogenesis. Several Tssk family proteins have extensively been studied. However, the exact function of Tssk4 remains unclear. A Tssk4 knockout mouse model was generated and the males were subfertile due to seriously decreased sperm motility. T...