Morphological changes of Campylobacter jejuni growing in liquid culture

Campylobacter jejuni growing in liquid culture was found to exhibit gross morphological changes with time. Exponentially growing cells showed typical short spiral forms. At mid-stationary phase the cells became approximately twice the length of the exponential forms. Late stationary/early decline phase cells were seen to be a mixture of coccal forms and cells which were between 3 and 4 times the length of exponentially growing cells. Continued incubation of cultures eventually resulted in a population largely of coccal forms. These morphological changes have not previously been observed when Camp. jejuni has been grown on agar-based solid medium. It is likely that such changes result from the differential expression of genes that control the timing of cell division.