Nonetheless, diffusion considerations do explain how bacteria can increase their nutrient harvesting efficiency by altering their gross morphology. Caulobacter crescentus is
a curved cell of E. coli-like dimensions that produces a thin, elongated stalk (prostheca) that extends from one pole and affixes the organism to solid surfaces in its
aqueous environment [14]. The length of the stalk appears to be regulated by the availability of nutrients because phosphate-poor conditions induce longer stalks
in this and similar bacteria [14–16]. Recently, Wagner et al. produced strong support for the idea that this simple change in cell shape is a physically useful response [17].
They confirmed the existence of stalk-mediated phosphate
uptake and demonstrated mathematically that cells
import more phosphate by extruding a long, thin stalk
than they would if they were merely filamented [17].
This is solid experimental evidence that cell shape, in and
of itself, affects nutrient acquisition and argues that other
nutritional situations may create conditions that favor one
bacterial shape over another.
Mo