The contraction process of living Vorticella sp. has been investigated by image processing using a high-speed video camera. In order to express the temporal change in the stalk length resulting from the contraction, a damped spring model and a nucleation and growth model are applied. A double exponential is deduced from a conventional damped spring model, while a stretched exponential is newly ...

We show through calculations, simulations and experiments that the eddies often observed near sessile filter feeders are frequently due to the presence of nearby boundaries. We model the common filter feeder Vorticella, which is approximately 50 microm across and which feeds by removing bacteria from ocean or pond water that it draws towards itself. We use both an analytical stokeslet model and...

Escherichia coli O157:H7 (EcO157) associated with the 2006 spinach outbreak appears to have persisted as the organism was isolated, three months after the outbreak, from environmental samples in the produce production areas of the central coast of California. Survival in harsh environments may be linked to the inherent fitness characteristics of EcO157. This study evaluated the comparative fitn...

A survey was carried out on the prevalence of bacteria and ciliate protozoan of Pellaells indiclls obtained from Ennore estuary, Chennai (Madras), India from November 1989 to July 1992. The study r~vealed the occurrence of Vibrio parahaemolyticus, V. VUlllijiCUS, V. harvey;, V. allguillarum, V. damsela, Pseudomollas sp., P. aemgillo.\'{/ and a tilamentous bacterium Leucothrix sp. This study als...

Try to imagine a fast biological movement. Perhaps you visualize the twitch of an eye or the flicker of a boxer’s jab. These movements may seem fast, but in this issue of Biophysical Journal, Upadhyaya and colleagues take biological speed to a whole new level by analyzing the contractions of Vorticella, a wineglass shaped ciliated protist (1). When a Vorticella cell is frightened, it can contra...

The millisecond stalk contraction of the sessile ciliate Vorticella convallaria is powered by energy from Ca2þ binding to generate contractile forces of ~10 nN. Its contractile organelle, the spasmoneme, generates higher contractile force under increased stall resistances. By applying viscous drag force to contracting V. convallaria in a microfluidic channel, we observed that the mechanical for...