Related papers: Filter-feeding, near-field flows, and the morpholo…
The recent discovery of the striking sheet-like multicellular choanoflagellate species $Choanoeca~flexa$ that dynamically interconverts between two hemispherical forms of opposite orientation raises fundamental questions in cell and…
As the closest unicellular relatives of animals, choanoflagellates serve as useful model organisms for understanding the evolution of animal multicellularity. An important factor in animal evolution was the increasing ocean oxygen levels in…
As the closest living relatives of animals, choanoflagellates exhibit remarkable diversity. Even their microvilli collar, used to filter and capture food, varies significantly among species. This diversity suggests either strong…
Ciliated microorganisms near the base of the aquatic food chain either swim to encounter prey or attach at a substrate and generate feeding currents to capture passing particles. Here, we represent attached and swimming ciliates using a…
We illuminate the nature of the three-dimensional random walks of microorganisms composed of individual organisms adhered together. Such $aggregate~random~walkers$ are typified by choanoflagellates, eukaryotes that are the closest living…
Eukaryotic swimming cells such as spermatozoa, algae or protozoa use flagella or cilia to move in viscous fluids. The motion of their flexible appendages in the surrounding fluid induces propulsive forces that balance with the viscous drag…
Sponges, the basalmost members of the animal kingdom, exhibit a range of complex architectures in which microfluidic channels connect multitudes of spherical chambers lined with choanocytes, flagellated filter-feeding cells. Choanocyte…
We study the stochastic hydrodynamics of colonies of flagellated swimming cells, typified by multicellular choanoflagellates, which can form both rosette and chainlike shapes. The objective is to link cell-scale dynamics to colony-scale…
Micro-organisms can be classified into three different types according to their size. We study the efficiency of the swimming of micro-organism in two dimensional fluid as a device for helping the explanation of this hierarchy in the size.…
Cells swimming in viscous fluids create flow fields which influence the transport of relevant nutrients, and therefore their feeding rate. We propose a modeling approach to the problem of optimal feeding at zero Reynolds number. We consider…
Interactions between microorganisms and their complex flowing environments are essential in many biological systems. We develop a model for microswimmer dynamics in non-Newtonian Poiseuille flows. We predict that swimmers in…
Several micro-organisms, such as bacteria, algae, or spermatozoa, use flagella or cilia to swim in a fluid, while many other micro-organisms instead use ample shape deformation, described as amoeboid, to propel themselves by either crawling…
One approach to quantifying biological diversity consists of characterizing the statistical distribution of specific properties of a taxonomic group or habitat. Microorganisms living in fluid environments, and for whom motility is key,…
Some microorganisms, such as spermatozoa, synchronize their flagella when swimming in close proximity. Using a simplified model (two infinite, parallel, two-dimensional waving sheets), we show that phase-locking arises from hydrodynamics…
Cells swimming in confined environments are attracted by surfaces. We measure the steady-state distribution of smooth-swimming bacteria (Escherichia coli) between two glass plates. In agreement with earlier studies, we find a strong…
Suspensions of unicellular microswimmers such as flagellated bacteria or motile algae exhibit spontaneous density heterogeneities at large enough concentrations. Based on the relative location of the biological actuation appendages i.e.…
Unicellular microscopic organisms living in aqueous environments outnumber all other creatures on Earth. A large proportion of them are able to self-propel in fluids with a vast diversity of swimming gaits and motility patterns. In this…
A central challenge for organisms during development is determining a means to efficiently export toxic molecules from inside the developing embryo. For aquatic microorganisms, the strategies employed should be robust with respect to the…
Despite their importance in many biological, ecological and physical processes, microorganismal fluid flows under tight confinement have not been investigated experimentally. Strong screening of Stokelets in this geometry suggests that the…
Interactions between swimming cells and surfaces are essential to many microbiological processes, from bacterial biofilm formation to human fertilization. However, in spite of their fundamental importance, relatively little is known about…