scholarly journals Ciliary chemosensitivity is enhanced by cilium geometry and motility

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
David Hickey ◽  
Andrej Vilfan ◽  
Ramin Golestanian

Cilia are hairlike organelles involved in both sensory functions and motility. We discuss the question of whether the location of chemical receptors on cilia provides an advantage in terms of sensitivity and whether motile sensory cilia have a further advantage. Using a simple advection-diffusion model, we compute the capture rates of diffusive molecules on a cilium. Because of its geometry, a non-motile cilium in a quiescent fluid has a capture rate equivalent to a circular absorbing region with ~4x its surface area. When the cilium is exposed to an external shear flow, the equivalent surface area increases to ~6x. Alternatively, if the cilium beats in a non-reciprocal way in an otherwise quiescent fluid, its capture rate increases with the beating frequency to the power of 1/3. Altogether, our results show that the protruding geometry of a cilium could be one of the reasons why so many receptors are located on cilia. They also point to the advantage of combining motility with chemical reception.

2021 ◽  
Author(s):  
David Hickey ◽  
Andrej Vilfan ◽  
Ramin Golestanian

Cilia are hairlike organelles involved in both sensory functions and motility. We discuss the question of whether the location of chemical receptors on cilia provides an advantage in terms of sensitivity. Using a simple advection-diffusion model, we compute the capture rates of diffusive molecules on a cilium. Because of its geometry, a non-motile cilium in a quiescent fluid has a capture rate equivalent to a circular absorbing region with ~ 4× its surface area. When the cilium is exposed to an external shear flow, the equivalent surface area increases to ~ 10×. Alternatively, if the cilium beats in a non-reciprocal way, its capture rate increases with the beating frequency to the power of 1/3. Altogether, our results show that the protruding geometry of a cilium could be one of the reasons why so many receptors are located on cilia. They also point to the advantage of combining motility with chemical reception.


2009 ◽  
Vol 57 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Camila Aguirre Góes Rudorff ◽  
João Antônio Lorenzzetti ◽  
Douglas F. M. Gherardi ◽  
Jorge Eduardo Lins-Oliveira

The connectivity of marine populations via larval dispersal is crucial for the maintenance of fisheries production and biodiversity. Because larval dispersion takes place on different spatial scales, global operational satellite data can be successfully used to investigate the connectivity of marine populations on different spatial and temporal scales. In fact, satellite data have long been used for the study of the large and mesoscale biological processes associated with ocean dynamics. This paper presents simulations of spiny lobster larvae transport in the Tropical Atlantic using the geostrophic currents, generated by altimetry that feeds an advection/diffusion model. Simulations were conducted over the Tropical Atlantic (20ºN to 15ºS), considering four larvae release areas: the Cape Verde Archipelago, the Ivory Coast, Ascension Island and Fernando de Noronha Archipelago. We used mean geostrophic current (MGC) calculated from 2001 to 2005 to represent the mean circulation of the Tropical Atlantic. We also ran the model for the El Niño geostrophic current regime (ENGC) using part of the MGC data, representing the El Niño 2002/2003 event. Results suggest that the intensification of the mesoscale ocean processes associated with El Niño events promotes the connectivity between populations, increasing the chances of a genetic flux among different stocks. We concluded that the altimetry geostrophic current data together with a relatively simple advection/diffusion model can provide useful information about the physical dynamics necessary to conduct studies on larval dispersion.


NeoBiota ◽  
2020 ◽  
Vol 56 ◽  
pp. 73-88
Author(s):  
Ryan M. Utz ◽  
Alysha Slater ◽  
Hannah R. Rosche ◽  
Walter P. Carson

Monospecific stands of invasive plants can dramatically restructure habitat for fauna, thereby elevating population densities or promoting foraging of consumer species who benefit in the altered habitat. For example, dense stands of invasive plants may protect small mammals from predators, which in turn could increase foraging pressure on seeds that small mammals feed upon. We used a before-after, control-impact experimental design to test whether small mammal capture rates were higher and giving-up densities (GUDs) lower beneath dense stands of Berberis thunbergii, an invasive shrub with a rapidly expanding range throughout eastern North America. Our experimental design included three plot categories: 1) plots heavily invaded by B. thunbergii, 2) control plots lacking invasive shrub cover, and 3) invaded plots where we eradicated B. thunbergii midway through the study. Although our overall small mammal capture rate was low, small mammal captures were 65% higher in B. thunbergii invaded habitat relative to control plots and eradication lowered capture rates by 77%. GUDs were also 26% higher within B. thunbergii relative to control plots and eradication decreased GUDs by 65%. Our findings suggest that small mammals perceive dense stands of B. thunbergii as relatively safe foraging habitat. Prior surveys within our study locations revealed dramatically depressed tree seedling densities under B. thunbergii, thus invasive plants may promote intensive foraging by small mammals and reduce recruitment for species with foraged seeds or seedlings.


1991 ◽  
Vol 48 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Michele Dionne ◽  
Carol L. Folt

In this laboratory study we measured the independent effects of macrophyte growth form, plant density, and prey abundance on the foraging rate of the pumpkinseed sunfish (Lepomis gibbosus). We demonstrate that macrophyte growth forms are not all similar in their effects on fish foraging. Prey capture rates of pumpkinseeds foraging among Scirpus validus (cylindrical stems) were 53 and 365% times greater than for Potamogeton amplifolius (leafy stems) for cladoceran (Sida crystallina) and larval damselfly (Coenagrionidae) prey, respectively. Plant growth form influenced prey capture rates more than charges in natural plant density. Plant density effects ranged from none on damselfly capture rates to a 29% decline in cladoceran capture rate over a twofold increase in plant density. Our results indicate that in plant-structured habitats, variation in plant growth form can be an important determinant of fish foraging and habitat associations.


2004 ◽  
Author(s):  
Timothy J. Rennie ◽  
Jianming Dai ◽  
Vijaya G. S. Raghavan

2021 ◽  
Vol 93 ◽  
pp. 267-278
Author(s):  
E. García-Hernández ◽  
C.G. Aguilar-Madera ◽  
E.C. Herrera-Hernández ◽  
R. Ocampo-Pérez ◽  
E. Bailón-García ◽  
...  

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