Swarmer cell differentiation in Proteus mirabilis

Abstract

SummaryUnder the appropriate environmental conditions, the Gram-negative bacterium Proteus mirabilis undergoes a remarkable differentiation to form a distinct cell type called a swarmer cell. The swarmer cell is characterized by a 20-to 40-fold increase in both cell length and the number of flagella per cell. Environmental conditions required for swarmer cell differentiation include: surface contact, inhibition of flagellar rotation, a sufficient cell density and cell-to-cell signalling. The differentiated swarmer cell is then able to carry out a highly ordered population migration termed swarming. Genetic analysis of the swarming process has revealed that a large variety of distinct loci are required for this differentiation including: genes involved in regulation, lipopolysaccharide and peptidoglycan synthesis, cell division, ATP production, putrescine biosynthesis, proteolysis and cell shape determination. The process of swarming is important medically because the expression of virulence genes and the ability to invade cells are coupled to the differentiated swarmer cell. In this review, the genetic and environmental requirements for swarmer cell differentiation will be outlined. In addition, the role of the differentiated swarmer cell in virulence and its possible role in biofilm formation will be discussed.

Proteus sp. – an opportunistic bacterial pathogen – classification, swarming growth, clinical significance and virulence factors

“…Most probably putrescine can form a complex with galacturonic acid which is component of CPS. This suggests a possibility that putrescine complexed with cell surface polysaccharide acts as a signal factor or putrescine regulates expression of CPS (RATHER 2005, MORGENSTEIN et al 2010.…”

“…It was found that extracellular signal AI-2 (autoinducer-2) does not play a role in swarming. Cyclic dipeptides were also shown as P. mirabilis signaling molecules out of importance in swarming (RATHER 2005). Other signal molecules N-acyl homoserine lactones crucial in quorum sensing are not produced by P. mirabilis (MORGENSTEIN et al 2010).…”

“…A number of factors playing a role in swarming regulations have been recognized (DANIELS et al 2004, RATHER 2005, VERSTRAETEN et al 2008, MORGENSTEIN et al 2010. The most important gene involved in upregulation of flagellin production is flhDC, class 1 gene of flagellar regulon.…”

Diclofenac inhibits virulence of Proteus mirabilis isolated from diabetic foot ulcer

“…This form of motility allows P. mirabilis to migrate across the infected ulcer, spreading the infection (Rather, 2005; Jacobsen et al, 2008). Moreover, P. mirabilis biofilms contain protruding swarm cells which enhance the microbial resistance (Jones et al, 2007).…”

Characterization and Identification of an Agar-Degrading Motile Bacteria Strain

“…8.55 mM NaCl, 9.35 mM NH4Cl) 액체배지 또는 1.5% (w/v) agar를 첨가한 고체배지를 사용하여 37℃에서 배 양하였다 [3]. 최소배지는 M9 CK214 균주의 효소액을 분리하 기 위해서 0.2% (w/v) agar가 첨가된 LB 액체배지에서 24 시 간 동안 배양하였다.…”