Fractal spreading growth ofSerratia marcescenswhich produces surface active exolipids

Abstract

An irregular fiord‐like outline of a S. marcescens colony expanding on a hard agar medium was shown to be fractal which promised an extremely long array of outermost cells. For the analysis of such spreading growth, mutants defective in production of surface active exolipids (serrawettin W1 and W3) and flagella‐less mutants were isolated. The fractal spreading growth was found to be correlated with serrawettin production. Furthermore, serrawettin‐less mutants demonstrated spreading growth when purified serrawettin W1 or W3 were supplied exogenously.

Detection and avoidance of a natural product from the pathogenic bacterium Serratia marcescens by Caenorhabditis elegans

“…Serrawettin W2 production is an attribute of a remarkably limited number of bacteria: not only is it specific to S. marcescens, but it is present only in particular strains. Other strains produce the structurally distinct serrawettins W1 or W3 (25). C. elegans avoided W1-and W3-producing strains of S. marcescens but not isogenic mutants that did not produce the respective serrawettins (data not shown).…”

Cooperative self-organization of microorganisms

“…Serratia marcescens produces (as do other species of Serratia) a wetting¯uid which is essential for its surface translocation and for the formation of colonial branched patterns [76,148,149]. The essential element of this wetting¯uid is a surfactant, serrawettin.…”

Pattern Formation of Bacterial Colonies byEscherichia coli

“…Some observed patterns seem to be universal in that they are observed for other pattern-forming phenomena as well. For instance, diffusion-limited aggregation (DLA)-like, [2][3][4]11,[15][16][17][18][19][20] Eden-like, 6,7,[21][22][23] concentric-ring, [9][10][11][12][13][14]16,24) and dense branching morphology (DBM) 8,19,20) patterns are observed not only in bacterial colonies, but also in crystal growth and viscous fingering. 1) On the other hand, the difference in individuality among bacterial species clearly exists in terms of shape, motility, collective behavior, and secretion.…”

“…Then various bacterial species form DLA-like self-similar fractal colonies patterns. [2][3][4]11,15,16,20) Since the growth process of colonies in this case is simply limited by nutrient diffusion, 2) this kind of pattern has also been seen in nonbiological diffusion-limited systems such as electrochemical deposition, dielectric breakdown, viscous fingering, and crystal growth. 19) On the other hand, under the opposite condition that C a is low and C n is high, the cell motility is high and the cell multiplication is very active.…”

“…1) We have so far inquired closely into the pattern formation of bacterial colonies formed on the surface of semisolid agar plates, using a variety of bacterial species such as Bacillus subtilis, [2][3][4][5][6][7][8][9][10] Proteus mirabilis, [11][12][13][14] and Serratia marcescens. 15,16) Such colonies exhibit various patterns, depending on environmental conditions. Some observed patterns seem to be universal in that they are observed for other pattern-forming phenomena as well.…”