From branching to nebula patterning during colonial development of the Paenibacillus alvei bacteria

We present the morphology diagram (morphologies as function of peptone levels and agar concentrations) observed during colonial development of Paenibacillus alvei bacteria. These bacteria are close to Paenibacillus dendritiformis and have been studied extensively in the past. Like P. dendritiformis, P. alvei produces a layer of lubricating fluid for movement on hard surfaces. Unlike P. dendritiformis which attempts to swim on hard surfaces, P. alvei main movement on hard surfaces is swarming, like the movement of P. cortex. Under some growth conditions P. alvei and P. vortex exhibit collective migration of clusters of bacteria and formation of bacterial vortices. Under different growth conditions P. alvei develop branching patterns. P. alvei also develop new class of patterns which we coin "nebula patterns". Modeling of the new patterns is still an open challenge. (C) 2000 Elsevier Science B.V. All rights reserved.