Living creatures exhibit a remarkable diversity of locomotion mechanisms,
evolving structures specialized for interacting with their environment. In
the vast majority of cases, locomotor behaviours such as flying, crawling
and running are orchestrated by nervous systems. Surprisingly, microorganisms can enact analogous movement gaits ...
Living creatures exhibit a remarkable diversity of locomotion mechanisms,
evolving structures specialized for interacting with their environment. In
the vast majority of cases, locomotor behaviours such as flying, crawling
and running are orchestrated by nervous systems. Surprisingly, microorganisms can enact analogous movement gaits for swimming using multiple,
fast-moving cellular protrusions called cilia and flagella. Here, I demonstrate
intermittency, reversible rhythmogenesis and gait mechanosensitivity in
algal flagella, to reveal the active nature of locomotor patterning. In addition
to maintaining free-swimming gaits, I show that the algal flagellar apparatus
functions as a central pattern generator that encodes the beating of each
flagellum in a network in a distinguishable manner. The latter provides a
novel symmetry-breaking mechanism for cell reorientation. These findings
imply that the capacity to generate and coordinate complex locomotor
patterns does not require neural circuitry but rather the minimal ingredients
are present in simple unicellular organisms.
This article is part of the Theo Murphy meeting issue ‘Unity and diversity
of cilia in locomotion and transport’.